Acromag ST133-16 0 Series User manual

USB Programmable, DIN Form B
Connection Head Transmitter
Model ST133-1600 & ST133-1610
Two-Wire Transmitter, T/C Input
USER’S MANUAL
ACROMAG INCORPORATED Tel: [phone]
30765 South Wixom Road email: [email protected]
Wixom, MI 48393-2417 U.S.A.
Copyright 2011, Acromag, Inc., Printed in the USA.
Data and specifications are subject to change without notice. 8500897H

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
___________________________________________________________________
______________________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
2
IMPORTANT SAFETY CONSIDERATIONS
You must consider the possible negative effects of power, wiring,
component, sensor, or software failure in the design of any type of
control or monitoring system. This is very important where property
loss or human life is involved. It is important that you perform
satisfactory overall system design and it is agreed between you and
Acromag, that this is your responsibility.
GETTING STARTED
DESCRIPTION….…………………….………..……….. 3
Ke
y
Features……………………………………… 3
A
pplication.…………..…………………………… 3
Mechanical Dimensions..……………………….. 4
ELECTRICAL CONNECTIONS.….……..…………….. 5
Sensor Input Connections…..…………………. 5
Output/Power Connections....…………………. 6
Earth Ground Connections……………….……. 7
USB Connections.……………………………….. 8
CONFIGURATION SOFTWARE…….……………….. 9
Introduction…………....………….………………. 9
TROUBLESHOOTING……...………………………….. 10
Dia
g
nostics Table.……………………………….. 10
TECHNICAL REFERENCE
BLOCK DIAGRAM…..……...………………………….. 13
CONFIGURATION STEP-BY-STEP………………….. 14
Calibration Connections..…………..….……….. 14
Reconfi
g
uration…………………..………………. 16
Zero & Full-Scale Calibration…………….......... 20
Other Confi
g
uration Controls.………….…...… 22
SPECIFICATIONS……………………...…………….… 23
Model Numbers...……………….………….…….. 23
Input………………………………………………… 24
Output…………..………..……....………………… 26
USB Interface..……………………………………. 27
A
pprovals…..……………………………………... 28
Enclosure and Ph
y
sical…………………………. 28
Environmental…………………………………….. 29
Reliabilit
y
Prediction…………………………….. 29
Confi
g
uration Controls………………………….. 30
ACCESSORIES……………...………………………….. 30
Software Interface Packa
g
e……………………. 30
Transmitter Mountin
g
Kit……………………….. 30
USB Isolator…..….……………………………….. 30
USB A-B Cable…………………………..………. 31
USB A-mini B Cable……………………….……. 31
DIN Rail Adapte
r
Kit……………………………… 31
TABLE OF
CONTENTS
Symbols on equipment:
Means “Refer to User’s
Manual (this manual) for
additional information”.
The information of this manual
may change without notice.
Acromag makes no warranty
of any kind with regard to this
material, including, but not
limited to, the implied
warranties of merchantability
and fitness for a particular
purpose. Further, Acromag
assumes no responsibility for
any errors that may appear in
this manual and makes no
commitment to update, or
keep current, the information
contained in this manual. No
part of this manual may be
copied or reproduced in any
form without the prior written
consent of Acromag, Inc.
For additional information,
please visit our web site at
www.acromag.com and download
our whitepaper 8500-904,
Introduction to Two-Wire
Transmitters.
Windows® is a registered
trademark of Microsoft
Corporation.
!

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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3
The ST133-16x0 is an ANSI/ISA Type II transmitter designed to interface
with a thermocouple sensor (Type J, K, T, R. S, B, E, N), or millivoltage
(±100mV) input source, isolate the input signal, and modulate a 4-20mA
current signal to drive a two-wire current loop. This unit is setup and
calibrated using configuration software and a USB connection to Windows-
based PC’s (Windows XP and later versions only). The unit provides an
adjustable input range, T/C linearization, input isolation, break detection,
variable input filter, and cold-junction compensation.
Digitally setup and calibrated w/ Windows software via USB.
Designed for DIN Form B sensor head mounting.
High measurement accuracy and linearity.
T/C Type J, K, T, R, S, B, E, N, or ±100mV input support.
T/C inputs are linearized with respect to temperature.
T/C inputs include accurate Cold Junction Compensation.
Supports both Celsius and Fahrenheit temperature units.
Adjustable input ranges.
Variable Input Filter Adjustment.
Normal or Reverse Acting output.
Up-scale or down-scale lead-break/burnout detection.
Non-polarized two-wire current loop connections.
Convenient two-wire loop power.
Namur compliant loop current.
Wide ambient temperature operation.
Hardened For Harsh Environments.
Optional DIN Rail Adapter for T-type & G-type DIN rail.
CE Approved.
Model ST133-1610 is UL Listed (USA & Canada) suitable for use in
Class I, Division 2, Groups A, B, C, D Hazardous Locations, or
Nonhazardous Locations only.
Model ST133-1610 is ATEX Certified for Explosive Atmospheres.
II 3 G Ex nA IIC T4 Gc -40
o
C ≤Ta ≤+80
o
C
DEMKO 13 ATEX 1113348X
This transmitter is designed for mounting in DIN Form B connection/sensor
heads commonly used in thermowell applications for sensing temperature or
for use in an enclosure with suitable strength and rigidity. Optionally, a DIN-
rail adapter may be purchased for mounting the unit to T-type, or G-type
DIN rail. The transmitter must be installed in an ATEX Certified enclosure
with a minimum ingress protection rating of at least IP54. Enclosure must
have a door or cover accessible only by the use of a tool (See page 28 for
details).
This model isolates its input signal and can mate with grounded or non-
grounded thermocouple temperature probes common to thermowell
applications. It provides an output current linearized to the T/C sensor
temperature. Optionally, it supports a ±100mV input range and will drive an
output current linear to the sensor millivoltage.
The output signal is transmitted via a two-wire, 4-20mA current loop. The
two-wire current signal can be transmitted over long distances with high
noise immunity. Sensor lead-break detection and the inherent live-zero
output offset offers convenient I/O fault detection, should an input or output
wire break.
DESCRIPTION
Ke
y
Features
A
pplication

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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4
Note that this transmitter conforms to the mechanical limits set forth in the
German standard DIN 43 729, for the Form B head style, and can be easily
mounted in DIN Form B connection and thermowell protection heads, similar
to the figure at upper left.
The M4 mounting screws and relief springs used to attach the transmitter to
the connection head are ordered separately via Acromag Mounting Kit
ST130-MTG (see Accessories section).
The unit may be optionally mounted to 35mm T-type or G-type DIN rail
using the optional DIN mounting kit ST130-DIN as shown at left (see
Accessories section).
44.50
1.7 5 2
33.00
1.2 9 9
16 .5 0
.6 5 0
20.0°
5.28
.2 0 8
23.40
.9 2 1
12 .9 6
.5 10
Dimensions in millimeters (inches)
10 . 4 4
.4 11
O5.15
.2 0 3
O6.48
.2 5 5
Mechanical Dimensions
Connection Head Mounting
DIN Rail Mounting
35mm T-Type DIN Rail
G-Type DIN Rail

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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5
WARNING – EXPLOSION HAZARD – Do not disconnect equipment unless
power has been removed or the area is known to be non-hazardous.
WARNING – EXPLOSION HAZARD – Substitution of any components may
impair suitability for Class I, Division 2.
WARNING – EXPLOSION HAZARD – The area must be known to be non-
hazardous before servicing/replacing the unit and before installing.
Wire terminals can accommodate 14-28 AWG (2.08-0.081mm2) solid or
stranded wire. Input wiring may be shielded or unshielded type. Ideally,
output wires should be twisted pair. Strip back wire insulation 3/8-inch on
each lead and wrap the bare wire in a clockwise direction around the
terminal screw and below the SEMS washer. Tighten the screw to secure
the wire at a torque rating range of 0.226 to 0.282 N-m. Terminals include
wire loops for test clip attachment, or for redundant soldered wire
connection required for heavy shock and vibration applications. Since
common mode voltages can exist on signal wiring, adequate wire insulation
should be used and proper wiring practices followed. Output wires are
normally separated from input wiring for safety, as well as for low noise
pickup. Cables and/or conductors in conduit must have a minimum
temperature rating of 110°C.
Sensor wires are passed up through the center of the transmitter and wire
directly to transmitter input terminals 2 and 3, as shown in the connection
drawings below. Observe proper polarity when making input connections.
Input signal is isolated.
T/C inputs use input terminals 2 & 3 – Terminal 2 is the positive input,
and terminal three is the negative input. Observe proper polarity. See
connection figure below. Note that you can optionally connect earth
ground at terminal 1 if the input sensor is un-grounded. This will help
improve transient input protection in noisy environments.
T1
T2
T3
T4 T5
T6
+
-
1
+
-
IN+
IN-
IN OUT
2
3
45
6
USB
1
2
3
4
NC
T/C
MODEL ST133-1600 INPUT SENSOR WIRING
SHIELDED CABLE
OPT SHIELD GROUND
INPUT
TERMINALS
NC
NOTE 1: DO NOT GROUND THE INPUT SENSOR IF UNIT IS
CONNECTED TO A PC WITHOUT USING A USB ISOLATOR,
OR IF CONNECTING EARTH GROUND AT TERMINAL 1.
(SEE NOTE 1)
EARTH GND
OPTIONAL
OPTIONAL EARTH GROUND
(FOR UNGROUNDED SENSORS)
ELECTRICAL
CONNECTIONS
Sensor Input
Connections
!

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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6
This transmitter has an ANSI/ISA Type 2 output in which the unit’s power
and output signal share the same two leads, and the transmitter output has
a floating connection with respect to earth ground. In these applications,
output wires normally pass through the output channel on top of the
transmitter and are drawn through the egress path of the connection head.
Connect a DC power supply and load in series in the two-wire loop as
shown in the drawing below.
Output connections are not polarized. The + and – designations are for
reference only with current normally input to Output+ and returned via
Output- (current sinking).
Loop supply voltage should be from 12-32V DC with the minimum
voltage level adjusted to supply over-range current to the load, plus 12V
across the transmitter, plus any transmission line drop.
Variations in power supply voltage between the minimum required and
32V maximum, has negligible effect on transmitter accuracy.
Variation in load resistance has negligible effect on output accuracy, as
long as the loop supply voltage is set accordingly.
Note the traditional placement of earth ground in the current loop. The
transmitter output floats off this ground by the voltage drop in the load
resistance and lead-wire.
Always connect the output/power wires and apply loop power before
connecting the unit to USB.
The output of this transmitter has a floating connection relative to ground
which makes it flexible in the way it connects to various “Receiver” devices.
In most installations, the loop power supply will be local to either the
transmitter, or local to the remote receiver. Shielded twisted pair wiring is
often used to connect the longest distance between the field transmitter and
the remote receiver. The receiver device is commonly the input channel of
a Programmable Logic Controller (PLC), a Digital Control System (DCS), or
a panel meter. Some receivers already provide excitation for the transmitter
and these are referred to as “sourcing” inputs. Other receivers that do not
provide excitation are referred to as “sinking” inputs, and these will require
that a separate power supply connect within the loop. Here are example
transmitter connection diagrams for “sourcing” and “sinking” receiver types:
WARNING: For compliance to applicable safety and performance
standards, the use of twisted pair output wiring is recommended. Failure
to adhere to sound wiring and grounding practices as instructed may
compromise safet
y
, performance, and possibl
y
dama
g
e the unit.
T1
T2
T3
T4 T5
T6
+
-
1
+
-OUT+
IN OUT
2
3
45
6
USB
6
5
OUTPUT
TERMINALS
OUT-
+
-
+
I
DC SUPPLY
(12-36V)
+
-
ST133-16X0 OUTPUT/POWER WIRING
EARTH
GROUND
I
I
NOTE: OUTPUT TERMINALS ARE NOT POLARIZED
PLUS & MINUS LABELS ARE FOR REFERENCE ONLY.
R
LOAD
-
THIS TRANSMITTER IS LOOP POWERED
4-20mA
12V MIN
MIN = 12V + 0.024*Rload
ELECTRICAL
CONNECTIONS
Output/Power
Connections

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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7
TIP - Ripple & Noise: Power supply ripple at 60Hz/120Hz is normally
reduced at the load by the transmitter, but additional filtering at the load can
reduce this ripple further. For large 60Hz supply ripple, connect an external
1uF or larger capacitor directly across the load to reduce excessive ripple.
For sensitive applications with high-speed acquisition at the load, high
frequency noise may be reduced significantly by placing a 0.1uF capacitor
directly across the load, as close to the load as possible.
TIP - Inductive Loads: If the two-wire current loop includes a highly
inductive load (such as an I/P current-to-pressure transducer), this may
reduce output stability. In this case, place a 0.1uF capacitor directly across
the inductive load and this will typically cure the problem.
The unit housing is plastic and does not require an earth ground connection.
If the transmitter is mounted in a metal housing, a ground wire connection is
typically required and you should connect the metal enclosure’s ground
terminal (green screw) to earth ground using suitable wire per applicable
codes. See the Electrical Connections Drawing for Output/Power and note
the traditional position of earth ground for the two-wire output current loop.
The Type II transmitter output terminals have a floating connection relative
to earth ground. Earth ground is normally applied at the output loop power
minus terminal and in common with the loop load or loop receiver minus.
Earth ground may optionally be applied at input terminal 1, if you are
connected to an ungrounded input signal.
Respect the traditional position of earth ground in a two-wire current
loop and avoid inadvertent connections to earth ground at other points,
which would drive ground loops and negatively affect operation.
Input connections and USB connections are isolated from the output.
Grounded or un-grounded input probes may be used. A USB isolator is
recommended for safety and noise suppression, but is not required for
this model, except when connected to a grounded input signal. Note
that most Personal Computers earth ground their USB ports and this
makes contact with both the signal and shield grounds which is held in
common to the input circuit ground.
ELECTRICAL
CONNECTIONS
Output/Power
Connections
Earth Ground
Connections

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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8
This transmitter is setup, configured, and calibrated via configuration
software that runs on a Windows-based PC connected to the unit via USB
(Windows XP or later version required). Refer to the drawing below to
connect your PC or laptop to the transmitter for the purpose of
reconfiguration and calibration using this software.
WARNING – USB Connector is not for operational or maintenance use
in hazardous locations. The intent of mating USB with this transmitter is
so that it can be conveniently setup and calibrated in a safe area, then
installed in its connection head, which may be in a hazardous area. Do not
attempt to connect a PC or laptop to this unit while installed in a hazardous
area, as USB energy levels could ignite explosive gases or particles in the
air.
USB Signal Isolation is Recommended and Required when also
connected to a grounded input – Input and USB connections are
isolated from the output of this model. USB Isolation is recommended
for safety and noise suppression reasons, but required when the input
signal is also grounded (i.e. when non-insulated or grounded probes are
used). You may use Acromag model USB-ISOLATOR to isolate your
USB port, or you can optionally use another USB signal isolator that
supports USB Full Speed operation (12Mbps).
Reconfiguration Requires USB and Loop Power - This transmitter
draws power from both the current loop, and from USB during setup and
calibration for any step that requires feedback of the output signal.
Otherwise, USB power alone is sufficient to change setup parameters
that do not refer to the output signal level.
Connect Loop Power Before USB - Always connect the transmitter to
its loop power supply before connecting USB in order to calibrate the
unit, or erratic operation may result.
IMPORTANT: USB logic signals to the transmitter are referenced to the
potential of the transmitter’s input ground. This ground is held in common
with USB ground and USB cable shield ground. While the input circuit and
USB circuit are isolated from the output, the USB port is not isolated from
the input. If the T/C or input signal is also earth grounded, then a ground-
loop will develop between the T/C ground and the earth ground of the PC
connected via USB, unless a USB isolator is used. The presence of this
ground loop causes the input bias to connect to ground and will negatively
affect performance. An isolator is required when the input signal is
grounded and the unit is connected to the USB port of a PC, or if input
terminal 1 is connected to earth ground. You could avoid the use of an
isolator if a battery powered laptop was used to connect to the transmitter,
and the laptop has no other earth ground connection.
ELECTRICAL
CONNECTIONS
USB Connections
!

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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9
USB Interface
Scans for connected transmitters and allows you to selectively open
communications with them.
Devices Found: Connected transmitters are listed in this pull-down
select menu. Click to highlight a transmitter and then click the “Open”
button to open communications with it.
Open/Close Button: Click this button to open or close communication
with the selected transmitter listed in the Devices Found field.
Displays the model number (Product Name), Manufacturer, and Serial
Number of the connected/selected transmitter.
The software automatically scans for connected transmitters when it is
booted. You can select a connected transmitter and open communications
with it from the Device Found pull-down menu. The connected/selected
transmitter’s ID info (Product Name/serial, Manufacturer, & Serial Number)
is also displayed. Device connection status messages are also indicated in
the System Message Window at the bottom of the screen.
Configuration Area
Input Type: Set the Input Type, J, K, T, E, R, S, B, N, or ±100mV.
Break Control: Set the break detection direction (Up or Down).
Filter Control: Set the level of filtering to be applied to the input signal.
CJC Control: Select if the CJC is used (On or Off).
I/O Scaling: Select the input range endpoints to scale to the 4 to 20mA
output range endpoints. You can optionally set this up for a reverse-
acting output by swapping the signals.
CONFIGURATION
SOFTWARE
Introduction
This transmitter can only be
configured and calibrated via
its Configuration Software and
a USB connection to your PC
or laptop. The configuration
software can be downloaded
free of charge from our web
site at www.acromag.com.
This software is also included
on a CDROM bundled with the
Configuration Kit ST13C-SIP
(see Accessories section).
For this model, look for
program ST133Config.exe.
The software is compatible
with XP or later versions of the
Windows operating system.
The configuration software
screen for this model is shown
at left. The configuration
screen is divided into five
sections as follows: USB
Interface, Configuration, Test,
Calibration, and the Message
Bar and controls at the bottom
of the screen. Additionally,
there is a Reset button, a
button to restore the unit to the
factory default state, and a
button to exit the program. A
short description of each of
these groups follows. For a
detailed explanation, see
Configuration Step-by-Step in
the Technical Reference
section of this manual.
HELP – You can press F1 for
Help on a selected or
highlighted field or control.
You can also click the [?]
button in the upper-right hand
corner of the screen and then
click to point to a field or
control to get a Help message
pertaining to the item you
pointed to.

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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10
Use the controls of the Configuration section to select an input type, the
break detent, filter level, CJC on/off, and input range scaling.
Test Input Area
Polling Toggle & Input Display Field: This button will toggle polling of
the input on/off and display the input level in the adjacent field.
Calibration Area (See Configuration Step-by-Step for Procedure)
Input: This section calibrates the selected input range.
Output: This section calibrates the 4 to 20mA output.
TRef: This section calibrates the cold-junction temperature reference
for cold junction compensation of the T/C.
Restore Factory Calibration Button: This button will restore only the
original factory calibration to the unit. Note that this will not reset any of
the configuration settings.
This section is used to calibrate the input, output, and CJC temperature
sensor of the unit. Instructions on how to calibrate the unit is detailed in the
Configuration Step-by-Step section of the Technical Reference portion of
this manual.
Message Bar
Displays the Fault Status of your transmitter input signal.
Displays prompt instructions during calibration.
The system message bar at the bottom of the screen will display & repeat
prompt instructions as you step through calibration. It also displays
diagnostic messages (see Configuration Step-by-Step section for specific
messages).
Other Options:
Reset ST133: This button will reset the ST133 unit.
Restore to Out of Box Condition: This button will restore ALL
configuration settings and calibration to the their original factory settings.
You can click the “Restore Factory Settings” button if you ever mis calibrate
or misconfigure a transmitter in such a way that its operation appears
erratic.
POSSIBLE CAUSE POSSIBLE FI
X
Cannot Communicate with Transmitter via USB…
A missing USB Isolator
could cause a ground loop
between a grounded input
sensor and earth ground at
the connected Personal
Computer’s USB port.
Without a USB isolator, a ground loop is
created between a grounded input signal
source and earth ground of the PC USB
port. It’s best to connect to USB via a
USB isolator for this reason, and for
increased safety and noise immunity.
Use an isolator like the Acromag USB-
ISOLATOR. Otherwise, use a battery
powered laptop to configure the
transmitter which does not normally earth
g
round its USB port.
CONFIGURATION
SOFTWARE
Introduction
You can click on “File” in the
upper left hand corner to open
a previously saved file, save
your own file, or print out your
configuration.
You can refer to the
Configuration Step-by-Step
section of the Technical
Reference portion of this
manual for a more detailed
description of every control
described here.
TROUBLE-SHOOTING
Diagnostics Table

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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11
POSSIBLE CAUSE POSSIBLE FI
X
Cannot Calibrate The Output…
Loop power ON to the unit? Unit requires a loop power connection,
even when connected to USB if you are
calibrating. The loop power supply should
also be present before connecting to
USB.
Software Fails to Scan/Detect Transmitter…
Bad USB Connection Recheck USB Cable Connection
Loop power was enabled
after connecting to USB.
You must enable the loop power supply
before connecting to USB. With loop
power present, disconnect then reconnect
the USB cable to the transmitter.
USB has not enumerated
the device.
Use the reset button on the Acromag USB
isolator to trigger renumeration of the
transmitter, or simply unplug/replug the
USB cable to the transmitter.
Communication or power
was interrupted while USB
was connected and the
configuration software was
runnin
g
.
Close the current connection with the
software, re-scan the transmitter, select
and re-open the transmitter for
communication (or simply exit the
Confi
g
uration software and reboot it
)
.
Output Erratic, Not operationa
l
, or at Wrong Value…
Missing USB isolation with
grounded input signal
source.
OR
You are also connecting
earth ground to terminal 1
and your input sensor is
already grounded. The
optional ground connection
at Terminal 1 is only for
un
g
rounded input sensors.
Even though the input is isolated from the
output, if your input sensor is grounded,
then connecting USB to the transmitter
will drive a ground loop between your
input and earth ground at the PC. Use
USB signal isolation, or alternatively, you
can connect to a battery-powered laptop,
which does not earth ground its USB
connection. Otherwise, you may have
connected earth ground at terminal 1 with
your input sensor already grounded,
which would cause the 1.25V input bias to
connect to input
g
round.
Otherwise… Verify loop power and voltage level.
Ideally, your supply voltage must be
adequate to provide 12V to the
transmitter, plus the IR drop in the load,
plus the IR drop in the lead wires, and all
at the maximum loop current
(
24mA
)
.
For input step, output a
p
pears to make
2
steps to reach its final value…
For a step change in the
input, the A/D needs 2 input
samples to charge to its final
level.
When you step the input signal, it takes
two samples for the A/D to charge up to
its final value, and this is evident when
using a scope to examine the output
transition in response to a step change at
the input, which appears to make two
steps to arrive at its final level.
TROUBLE-SHOOTING
Diagnostics Table
Before attempting repair or
replacement, be sure that all
installation and configuration
procedures have been
followed and that the unit is
wired properly. Verify that
power is applied to the loop
and that your loop power
supply voltage is sufficient to
supply over-scale current into
the load (MIN 0.020*Rload),
plus 9V at the unit terminals,
plus any line drop.
If your problem still exists after
checking your wiring and
reviewing this information, or if
other evidence points to
another problem with the unit,
an effective and convenient
fault diagnosis method is to
exchange the questionable
unit with a known good unit.
Acromag’s Application
Engineers can provide further
technical assistance if
required. Repair services are
also available from Acromag.

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
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Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
12
POSSIBLE CAUSE POSSIBLE FI
X
Output shifts of
f
-range when
y
ou connect USB…
Indicative of a ground fault
between earth ground at the
PC and earth ground applied
at the input sensor, which
causes the 1.25V input bias
to connect to input
g
round.
Only connect to the unit via isolated USB
if your input sensor is grounded. You
can connect without USB isolation if the
input signal is not already grounded.
Output goes to Over
-
Range
(
24mA
)
or Under-Range Limit
(
3.5mA
)
…
This indicates that either the
input signal is out of range, or
a sensor lead has broken and
caused lead break detection
to send the output to its
upscale or downscale detent.
It can also occur due to
contention between earth
ground at the PC USB port
and the input sensor.
Check the input signal with respect to
range and reduce or increase as
required to drive the output current within
its linear operating range. A fully
upscale or down-scale signal is normally
driven by a sensor fault, such as an open
sensor or broken sensor lead, and this
behavior follows the break control
setting. Also check the wiring of your
input sensor. If you are not isolating
USB, check for a ground loop between a
grounded T/C and earth ground of the
PC USB port.
Unit fails to operate or exhibits an output shift…
Is input grounded at terminal
1 and at the sensor?
Is USB isolation not being
used with a grounded
sensor?
Isolated models are intended for use with
ungrounded or grounded sensors, but
you can only connect to grounded
sensors if the USB signals are isolated.
Only connect earth ground at terminal 1
if your input is ungrounded. The input is
normally biased 1.25V off input ground to
allow negative signals, and a grounded
probe could inadvertently connect this
bias to earth ground with a non-isolated
USB connection to a PC, or with earth
g
round alread
y
connected at terminal 1.
Unit drives a low current, but fails to drive current at/near/above 20mA…
Loop supply voltage is too
low to support a full-scale or
over-range current level in the
loop load.
Check power voltage level. Make sure it
is at least 12V plus 0.020*Rload. If
transmission distance is long, then it
must have additional voltage to support
the IR drop in the wire. Ideally, the
voltage should have ample overhead to
drive the load at the maximum upscale
output current of 24m
A
.
Output holds last value when I connect USB…
Unit is awaiting initialization
via its configuration software
used to set it up and
configure it.
Boot the configuration software to regain
operation. The USB port is intended for
setup and configuration of the module
and it should not be left connected to
USB without also bootin
g
the software.
Cannot Calibrate Input Channel…
Is input wired properly? Check that input is wired to input
terminals 2 & 3 usin
g
correct polarit
y
.
TROUBLE-SHOOTING
Diagnostics Table
Service & Repair Assistance
This unit contains solid-state
components and requires no
maintenance, except for
periodic cleaning and
transmitter configuration
parameter (zero and full-scale)
verification. The potted
Surface Mounted Technology
(SMT) board contained within
this enclosure is nearly
impossible to repair, except for
firmware. It is highly
recommended that a non-
functioning transmitter be
returned to Acromag for repair,
replacement, or re-
programming. Acromag has
automated test equipment that
thoroughly checks and
calibrates the performance of
each transmitter, and restores
its firmware. Please refer to
Acromag’s Service Policy and
Warranty Bulletins on our web
site, or contact Acromag for
complete details on how to
obtain repair or replacement.

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
__________________________________________________________________
______________________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
13
R
12-36VDC
+-
~
~
20
LDO
REG
16-BIT DAC
+
-
LOOP+
LOOP-
4-20
mA
ISOLATED OUTPUT
24-BIT A/D
NV MEMORY
MICROCONTROLLER
TMP SENSOR
16-BIT DAC
REFERENCE
OSCILLATOR
EXCITATION
INPUT FILTER
INPUT BIAS
CJC TEMP
SENSOR
IN+
IN-
T/C
NC
1
2
3
4100K
1.25V
+3.3V
LDO
3.0V
3.0V
10M
10M
PULL+
PULL-
+2.5V
+2.5V
LDO
3.0V
+2.5V
MICROCONTROLLER 2
(USB-TO-SPI CONVERTER)
USB
+5V 3.0V
LEVEL
SHIFTERS
BUFFERS
+5V +2.5V
3.3V
OSC
3.3V
TWO-WIRE OUTPUT
PORT
POLARITY
PROTECTION
ISOLATED FLYBACK CONVERTER
TRI-STATE
BUFFERS
3.0V
ST133-16X0 SIMPLIFIED SCHEMATIC
(FILTERING AND DETAIL OMITTED FOR CLARITY)
T/C or mV INPUT
5
6
I
LOAD
EARTH
GROUND
ISOLATED OUTPUT
12-36V
DIGITAL
FILTER
COUNT ER
BUFFERS
INT ERNAL
PGA
MUX
SPI & RESET
TECHNICAL REFERENCE
This transmitter uses a microcontroller with an embedded multiplexer and
high-resolution A/D to convert the input signal to a serial digital pulse stream
that is then isolated via a pulse transformer and transmitted to a current-loop
DAC. Power for the isolated input side of the circuit is provided via an
isolated flyback converter that operates in parallel with the output loop.
Another microcontroller of the circuit is used to convert the external USB
signals to an internal SPI bus signal during reconfiguration. Setup involves
selecting the input type (T/C or Mv), upscale or downscale break detection,
turning CJC on or off as desired, selecting a filter level, and scaling the input
range endpoints to 4Ma and 20Ma at the output. A cold junction
compensation temperature sensor is located in the divider between the input
terminals. Output scaling can also be done in reverse to produce a reverse
acting output signal. The maximum over-range output signal is
approximately 24Ma, the under-range signal is 3.3Ma. Refer to the block
diagram above to gain a better understanding of how this transmitter works.
The input/USB and output/power circuits are isolated from each other. The
USB port ground is common to the input circuit ground. The USB port
ground of most PC’s is also common to the USB cable shield and earth
ground. Input sensors could be grounded or ungrounded. For this reason,
it is recommended that USB signals be isolated when connected to a PC to
prevent a ground loop from occurring between the PC earth ground and a
grounded input sensor, which would have the negative affect of pulling the
input bias supply to ground.
Block Dia
g
ram
Key Points of Operation
- Unit is Loop Powered
- Input is Isolated
- Input is Differential
- Output/Power Terminals are
Not Polarized
- Input circuit ground is
common to USB ground.
- USB powers a portion of the
input when connected.

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
___________________________________________________________________
______________________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
14
This section of the manual will walk you through the reconfiguration process
step-by-step. But before you attempt to reconfigure or recalibrate this
transmitter, please make the following electrical connections:
Calibration Connections:
1. Connect a precision voltage source or thermocouple calibrator to the
input as required, and observe proper polarity.
An accurate input source adjustable over the range desired for zero and
full-scale is required. A thermocouple calibrator may also be used. The
input source must be accurate beyond the unit specifications (better
than ±0.1%). A good rule of thumb is that your source accuracy should
be four times better than the rated accuracy you are trying to achieve
with the transmitter. For voltage inputs, use a voltage source with an
output impedance of 100or less.
In the absence of a thermocouple calibrator, a convenient method of
configuring the TC input would be to use a precision Mv source with the
module’s CJC set to OFF. Using this method allows the Mv source to
be wired directly to the input T/C terminals using copper wires. The
module’s cold junction compensation is turned off and the Mv values
applied to the input are the equivalent thermoelectric voltages that
correspond to the minimum and maximum temperatures of your desired
input range, and specific to each T/C type. Refer to the table of the
following page for a list of thermocouple voltages at specific
temperatures. After setting zero and full-scale in this manner, the CJC
switch should be returned back to the ON position to enable cold
junction compensation.
2. Wire an output current loop to the transmitter as shown in the Electrical
Connections section. You will need to measure the output current
accurately in order to calibrate the unit. You could connect a current
meter in series in this loop to read the loop current directly.
Alternatively, you could simply connect a voltmeter across a series
connected precision load resistor in the loop, then accurately read the
output current as a function of the voltage IR drop produced in this
resistor (recommended). In any case, be sure to power the loop with a
voltage that minimally must be greater than the 12V required by the
transmitter, plus the IR drop of the wiring and terminals, plus the IR drop
in the load. To compute the IR drop, be sure to use a current level that
considers the over-scale current (~24Ma). The output load resistance
and meter must be accurate beyond the unit specifications (better than
±0.1%). A good rule of thumb is that your load and meter accuracy
should be four times better than the rated accuracy that you are trying to
achieve with the transmitter.
Loop Power Supply: Make sure that your power supply voltage level
is at least 12V plus 0.020*load_resistance. Ideally, it should be great
enough to drive the over-range current of ~24Ma into your load (i.e.
greater than or equal to 12V+ 0.024*Rload, assuming the line drop is
negligible and the maximum possible over-range current.
Apply power to the transmitter output loop and always power the loop
before connecting to USB. You will not be able to calibrate the unit
without loop power applied.
CONFIGURATION
STEP-BY-STEP
Calibration
Connections
IMPORTANT: Do not connect
the transmitter to your PC via
USB without also booting the
configuration software.
Connection to USB is intended
as a temporary connection for
the purpose of setup and
reconfiguration only. If you
connect to USB but do not
boot the configuration, the
output DAC will hold its last
programmed value as the
unit’s microcontroller awaits
initialization via the host
runnin
g
confi
g
uration software.

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
__________________________________________________________________
______________________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
15
3. Connect the transmitter to the PC using the USB isolator and cables
provided in Configuration Kit ST13C-SIP (refer to Electrical Connections
section). You may omit the isolator if you are using a battery powered
laptop to connect to the unit, or if your input source is not already
grounded.
Now that you have wired the unit, applied power, and connected the unit
to USB, you can execute the Configuration Software program for your
model (ST132-ST133Config.exe) to begin reconfiguration. This
software is only compatible with XP or later versions of the Windows
operating system.
Thermocouple cromagtage Versus Temperature
(From the National Institute of Standards and Technology (NIST) Thermocouple Tables)
TEMP Thermoelectric Voltage In milliVolts (With Reference Junction at 0C)
C J K T E R S B N
- 260 --- -6.232 --- --- --- ---
- 250 --- --- -6.180 --- --- --- --- ---
- 230 --- --- -6.007 --- --- --- --- -4.226
- 210 -8.095 --- -5.753 --- --- --- --- -4.083
- 200 -7.890 -5.891 -5.603 -8.825 --- --- --- -3.990
- 150 -6.500 -4.913 -4.648 -7.279 --- --- --- -3.336
- 100 -4.633 -3.554 -3.379 -5.237 --- --- --- -2.407
- 50 -2.431 -1.889 -1.819 -2.787 -0.226 -0.236 --- -1.269
0 0.000 0.000 0.000 0.000 0.000 0.000 --- 0.000
+ 50 2.585 2.023 2.036 3.048 0.296 0.299 --- 1.340
+ 100 5.269 4.096 4.279 6.319 0.647 0.646 --- 2.774
+ 150 8.010 6.138 6.704 9.789 1.041 1.029 --- 4.302
+ 200 10.779 8.138 9.288 13.421 1.469 1.441 --- 5.913
+ 250 13.555 10.153 12.013 17.181 1.923 1.874 --- 7.597
+ 260 14.110 10.561 12.574 17.945 2.017 1.962 0.317 7.941
+ 300 16.327 12.209 14.862 21.036 2.401 2.323 0.431 9.341
+ 350 19.090 14.293 17.819 24.964 2.896 2.786 0.596 11.136
+ 390 21.297 15.975 20.255 28.146 3.304 3.164 0.746 12.603
+ 400 21.848 16.397 20.872 28.946 3.408 3.259 0.787 12.974
+ 450 24.610 18.516 --- 32.965 3.933 3.742 1.002 14.848
+ 500 27.393 20.644 --- 37.005 4.471 4.233 1.242 16.748
+ 550 30.216 22.776 --- 41.053 5.021 4.732 1.505 18.672
+ 600 33.102 24.905 --- 45.093 5.583 5.239 1.792 20.613
+ 650 36.071 27.025 --- 49.116 6.157 5.753 2.101 22.556
+ 700 39.132 29.129 --- 53.112 6.743 6.275 2.431 24.527
+ 760 42.919 31.628 --- 57.870 7.461 6.913 2.854 26.883
+ 800 --- 33.275 --- 61.017 7.950 7.345 3.154 28.455
+ 900 --- 37.326 --- 68.787 9.205 8.449 3.957 32.371
+ 950 --- 39.314 --- 72.603 9.850 9.014 4.387 34.319
+1000 --- 41.276 --- 76.373 10.506 9.587 4.834 36.256
+1200 --- 48.828 --- --- 13.228 11.951 6.786 43.846
+1300 --- 52.410 --- --- 14.629 13.159 7.848 47.513
+1372 --- 54.886 --- --- 15.645 14.033 8.642 ---
+1400 --- --- --- --- 16.040 14.373 8.956 ---
+1600 --- --- --- --- 18.849 16.777 11.263 ---
+1700 --- --- --- --- 20.222 17.947 12.433 ---
+1750 --- --- --- --- 20.877 18.503 13.014 ---
+1768 --- --- --- --- 21.101 18.693 13.223 ---
+1800 --- --- --- --- --- --- 13.591 ---
+1820 --- --- --- --- --- --- 13.820 ---
Note (Table): Shaded cells refer to the calibration range end points used to
calibrate the T/C type for this model. Bold column entries refer to the
nominal T/C input range end points of this model.
CONFIGURATION
STEP-BY-STEP
Calibration
Connections

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
___________________________________________________________________
______________________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
16
CONFIGURATION
STEP-BY-STEP
Reconfiguration
After executing the Acromag
Configuration software for this
model, a screen similar to the
one at right will appear, if you
have not already connected to
your transmitter via USB (note
some fields are faded out
under these conditions).
Note that without a device
already connected via USB,
the System Status window at
the bottom of the screen
prompts you to “Connect a
ST133 to a USB port”.
After you connect a transmitter
to the USB port, the software
will automatically detect it and
the screen will change similar
to the one at right.
Note that with a device already
connected via USB, the
System Status window
prompts you to “Select a
device from the drop down box
above and click Open”.
HELP – You can press F1 for
Help on a selected or
highlighted field or control.
You can also click the [?]
button in the upper-right hand
corner of the screen and click
to point to a field or control to
get a Help message pertaining
to the item
y
ou pointed to.

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
__________________________________________________________________
______________________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
17
At this point, you can select a device from the “Devices Found” field pull-
down menu by clicking on it, then clicking the “Open” button to connect to
the device for the purpose of reconfiguration and/or test (use the serial
number to discern a particular transmitter). The screen should then appear
similar to the one shown below. Note that “No error encountered while
reading configuration” is displayed in the System Message Window at the
lower left corner of the screen. Additionally, the device Product Name field
displays the Model, the Manufacturer field displays “Acromag, Inc.”, and the
Serial field displays this model’s serial number. Additionally, most of the
other fields and controls are not faded out and await your input.
If more than one transmitter was connected via USB through a hub, you can
discern which transmitter to open by referring to the product’s unique serial
number appended to the Product Name. If your intent was to open a
different transmitter on the hub, then you simply “Close” the current
connection and use the Devices Found scroll bar to select another
transmitter (discern by serial number), then click “Open” to open it for
communication. If you break the USB connection to a transmitter, the
software will display the following:
CONFIGURATION &
CALIBRATION
Reconfiguration
HELP – You can press F1 for
Help on a selected or
highlighted field or control.
You can also click the [?]
button in the upper-right hand
corner of the screen and click
to point to a field or control to
get a Help message pertaining
to the item
y
ou pointed to.

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
___________________________________________________________________
______________________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
18
After clicking “OK”, the software closes the connection and the screen
returns back to its initial state, prior to connecting a module to USB. When
you reconnect the USB cable, you will have to click “Open” to reopen
communication with the transmitter. If you have more than one transmitter
connected via a hub, then you will have to use the Device Name scroll bar
to first select a transmitter (discern unit by serial number), and then click
“Open” to open communication with it.
Note that if you intend to Test or Calibrate any elements of this transmitter,
you should already have loop power connected to the transmitter before you
execute this software.
At this point, the connected transmitter is ready for reconfiguration and the
appropriate configuration fields become active and await your input.
If you want to see how the connected unit is already configured before
changing its configuration, click the “Get Config From Unit” button of the
Configuration controls section to retrieve its current configuration
information. Note the message bar at the bottom of the screen and it should
display a message like “No error encountered while reading configuration”
Select the Input Type (T/C Type or ±100Mvdc)…
In the Configuration section of this screen, select an input type: T/C Type J,
K, T, R, S, E, B, N, or 100Mv.
If you select any T/C type, your output will be linear with respect to
sensor temperature, not sensor millivolts.
If you select “100Mv”, your output current will be linear with respect to
input voltage, not temperature, and no special linearization will be
performed. Note that “100Mv” represents ±100Mv range capability.
Select Upscale or Downscale Lead Break Detection…
Upon sensor burnout or a broken sensor lead, you can select “Downscale”
to send the output current to its down-scale limit (~3.5Ma), or “Upscale” to
send the output current to the over-scale limit (~24Ma). You can usually
discern, a lead break or open sensor from an over-range or under-range
input signal by noting its current level. Note that outputs can be reverse
acting, and upscale for a reverse acting output will remain ~24Ma. Likewise,
downscale for a reverse acting output still corresponds to a current level
~3.5Ma.
Select a Filter Control Level (None, Low, Medium, or High)…
Note that in addition to the analog filters of this unit, it also has the capability
of applying digital filtering. Increased filtering is useful to help minimize the
negative effects of noisy input signals, but will increase the response time of
the unit accordingly. You can select the amount of filtering as None, Low,
Medium, or High. Note the approximate response times indicated next to
each filter level.
CONFIGURATION
STEP-BY-STEP
Reconfi
g
uration

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
__________________________________________________________________
______________________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
19
Turn Cold Junction Compensation (CJC) On, or Off…
This model embeds a very accurate temperature sensor in the space
between the input + and – terminals in order to cold-junction compensate
the thermocouple signal. To explain, the voltage measured from the T/C
reflects the difference in temperature between each end. Thus, in order to
discern the actual temperature being sensed, it is necessary to know the
temperature at the other end, and this is usually referred to as the Cold
Junction.
Further, the connection between the thermocouple and the copper terminals
of the cold junction introduces additional thermocouples into the circuit.
However, because these errant thermocouples that occur at the junctions of
the ± terminals are close together and at identical temperatures, their effect
on the principal measurement cancels out of the derivation. But to keep
error to a minimum, you should still avoid any environmental or installation
effects that could drive a difference in temperature between the ± input
terminals. For example, touching one terminal and not the other.
You normally turn CJC On via this control for making T/C measurements,
but you can elect to turn it off temporarily, if you wish to calibrate the T/C
input using a voltage source that connects to the module via copper wires
(as opposed to the wire materials of the various thermocouple types).
Note: CJC temperature values are only resolved to 0.1°C using the internal
lookup tables for the T/C type. As such, units configured for small input
spans may appear less accurate with CJC ON, as ±0.1°C becomes a
greater percentage of a smaller span. Keep this in mind when resolving
measurements with short spans and high gains.
Set the I/O Scaling (You can set this up to be Reverse Acting, too) …
This control is used to map your input range, or a portion of your input
range, to the nominal 4Ma (0%) and 20Ma (100%) output range endpoints.
Refer to the specifications to determine the full input range capability of the
various input types. Then select valid input range endpoints to map to 4Ma
and to 20Ma. Note that it is possible to exchange the order of these value
assignments in order to define a reverse-acting output signal.
You need to select the input temperature or millivoltage that is to correspond
to 4Ma of output signal and type this value into the corresponding field for
4Ma output. You also need to do this for the 20Ma output endpoint.
Note: Note that the effective input resolution does not rescale itself for input
spans smaller than the nominal input range. That is, input resolution
diminishes proportionally as you reduce the input span with smaller input
ranges than nominal (see Specifications section for nominal ranges and
resolution).
Note that some under-range and over-range is built-into the unit, as the
output can swing as low as 3.5Ma, and as high as 24Ma. Actual endpoint
limits will vary slightly between units.
CONFIGURATION
STEP-BY-STEP
Reconfi
g
uration

Model ST133-16x0 Two-Wire T/C Transmitter w/USB
___________________________________________________________________
______________________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
20
If the input zero and full-scale points are chosen too close together (span
too small), resolution is diminished and the performance will be degraded.
A minimum effective span of 10Mv is recommended. Also, you should pick
your values carefully, as you will have to precisely drive the corresponding
input signal values for zero and full-scale in order to calibrate your input
range later.
(Optional) Test Your Input…
The Test Input area of your screen is useful to view your continuously
variable input measurement in the field adjacent to the Start/Stop Polling
button. Simply click the “Start Polling” toggle button, and the input will be
repeatedly polled and displayed in the adjacent field. Click this button again
to turn polling off.
Note that if CJC is ON, and your input signal is at 0°C (0.000Mv), the
temperature value displayed will be equivalent to the ambient temperature
at the input terminals (i.e. your cold junction). You can get a feel for how
stable CJC temperatures are by doing this.
You should turn polling off while trying to calibrate the unit, or change its
configuration.
Calibration of Input, Output, and Tref …
This section is used to calibrate the input, output, and cold junction
temperature reference of the unit. You can begin calibration of any of these
three stages by clicking the corresponding “Instructions” button and
following the on-screen prompts. Note that the button text will change
according to the step.
Each calibration is an interactive process in which the software prompts you
to apply input signals and then measure the corresponding output current.
First, it will prompt you to apply the zero input signal, then measure and
record the corresponding zero output signal current. Second, it does the
same for the full-scale input signal and the corresponding full-scale output
current signal. Note that as the span is reduced, resolution also diminishes.
The Configuration Software will usually let you know when you need to
adjust your desired limits as you enter them.
CAUTION: Input signal levels outside of the nominal input range of the unit
will not be accepted for configuration of zero or full-scale. Since not all input
levels can be validated during field programming, connecting or entering
incorrect signals will produce an undesired output response.
CONFIGURATION
STEP-BY-STEP
Reconfi
g
uration
Zero & Full-Scale
Calibration