Rockwell Automation micrologix 1200 User manual

Publication 1762-IN013A-EN-P - April 2002
Installation Instructions
MicroLogix™ 1200 Thermocouple/mV Input
Module
(Catalog Number 1762-IT4)
Inside…
Module Overview......................................................................................2
Description................................................................................................3
Module Installation...................................................................................3
System Assembly......................................................................................5
Mounting...................................................................................................6
Field Wiring Connections..........................................................................8
Cold-Junction Compensation (CJC)........................................................13
I/O Memory Mapping .............................................................................13
Specifications .........................................................................................16
Hazardous Location Considerations .......................................................21
Environnements dangereux ....................................................................22
For More Information..............................................................................23

2MicroLogix™ 1200 Thermocouple/mV Input Module
Publication 1762-IN013A-EN-P - April 2002
Module Overview
The thermocouple/mV modules receives and stores digitally converted
thermocouple and/or millivolt (mV) analog data from any combination of up to
four thermocouple or millivolt analog sensors. Each input channel is individually
configurable via software for a specific input device and provides open-circuit,
over-range and under-range detection and indication. The module receives all of its
+5V dc and +24V dc power from the 1762 expansion I/O bus. The module features
a terminal block with a cold-junction compensation (CJC) sensor.
Accepted Inputs Range
Thermocouple Type J -210 to +1200°C (-346 to +2192°F)
Thermocouple Type K -270 to +1370°C (-454 to +2498°F)
Thermocouple Type T -270 to +400°C (-454 to +752°F)
Thermocouple Type E -270 to +1000°C (-454 to +1832°F)
Thermocouple Type R 0 to +1768°C (+32 to +3214°F)
Thermocouple Type S 0 to +1768°C (+32 to +3214°F)
Thermocouple Type B +300 to +1820°C (+572 to +3308°F)
Thermocouple Type N -210 to +1300°C (-346 to +2372°F)
Thermocouple Type C 0 to +2315°C (+32 to + 4199°F)
millivolt inputs -50 to +50 mV
-100 to +100 mV

MicroLogix™ 1200 Thermocouple/mV Input Module 3
Publication 1762-IN013A-EN-P - April 2002
Description
Module Installation
1762 I/O is suitable for use in an industrial environment when installed in
accordance with these instructions. Specifically, this equipment is intended for use
in clean, dry environments (Pollution degree 2(1)) and to circuits not exceeding
Over Voltage Category II(2) (IEC 60664-1).(3)
Item Description Item Description
1a upper panel mounting tab 5 bus connector cover
1b lower panel mounting tab 6 flat ribbon cable with bus connector (female)
2 power diagnostic LED 7 terminal block
3 module door with terminal identification
label 8 DIN rail latch
4 bus connector with male pins 9 pull loop
(1) Pollution Degree 2 is an environment where, normally, only non-conductive pollution occurs except that occasionally a
temporary conductivity caused by condensation shall be expected.
(2) Over Voltage Category II is the load level section of the electrical distribution system. At this level transient voltages are
controlled and do not exceed the impulse voltage capability of the product’s insulation.
(3) Pollution Degree 2 and Over Voltage Category II are International Electrotechnical Commission (IEC) designations.
1a
1b
2
6
8
1a
1b
5
2
3
9
4
6
7

4MicroLogix™ 1200 Thermocouple/mV Input Module
Publication 1762-IN013A-EN-P - April 2002
Prevent Electrostatic Discharge
Remove Power
ATTENTION
!
Electrostatic discharge can damage integrated circuits or
semiconductors if you touch bus connector pins. Follow these
guidelines when you handle the module:
•Touch a grounded object to discharge static potential.
•Wear an approved wrist-strap grounding device.
•Do not touch the bus connector or connector pins.
•Do not touch circuit components inside the module.
•If available, use a static-safe work station.
•When not in use, keep the module in its static-shield box.
ATTENTION
!
Remove power before removing or installing this module.
When you remove or install a module with power applied, an
electrical arc may occur. An electrical arc can cause personal
injury or property damage by:
•sending an erroneous signal to your system’s field devices,
causing unintended machine motion
•causing an explosion in a hazardous environment
•causing permanent damage to the module’s circuitry
Electrical arcing causes excessive wear to contacts on both the
module and its mating connector. Worn contacts may create
electrical resistance.

MicroLogix™ 1200 Thermocouple/mV Input Module 5
Publication 1762-IN013A-EN-P - April 2002
System Assembly
The expansion I/O module is attached to the controller or another I/O module by
means of a ribbon cable after mounting as shown below.
TIP Use the pull loop on the connector to disconnect modules. Do
not pull on the ribbon cable.
WARNING
!
EXPLOSION HAZARD
•In Class I, Division 2 applications, the bus connector must
be fully seated and the bus connector cover must be
snapped in place.
•In Class I, Division 2 applications, all modules must be
mounted in direct contact with each other as shown on
page 7. If DIN rail mounting is used, an end stop must be
installed ahead of the controller and after the last 1762
I/O module.

6MicroLogix™ 1200 Thermocouple/mV Input Module
Publication 1762-IN013A-EN-P - April 2002
Mounting
Minimum Spacing
Maintain spacing from
enclosure walls, wireways,
adjacent equipment, etc.
Allow 50.8 mm (2 in.) of
space on all sides for
adequate ventilation, as
shown:
ATTENTION
!
Do not remove protective debris strip until after the module and
all other equipment near the module is mounted and wiring is
complete. Once wiring is complete and the module is free of
debris, carefully remove protective debris strip. Failure to
remove strip before operating can cause overheating.
TIP 1762 expansion I/O may be mounted horizontally only.
ATTENTION
!
During panel or DIN rail mounting of all devices, be sure that
all debris (metal chips, wire strands, etc.) is kept from falling
into the module. Debris that falls into the module could cause
damage when power is applied to the module.
Side Side
Top
Bottom
MicroLogix 1200
1762 I/O 1762 I/O 1762 I/O

MicroLogix™ 1200 Thermocouple/mV Input Module 7
Publication 1762-IN013A-EN-P - April 2002
DIN Rail Mounting
The module can be mounted using the following DIN rails: 35 x 7.5 mm
(EN 50 022 - 35 x 7.5) or 35 x 15 mm (EN 50 022 - 35 x 15).
Before mounting the module on a DIN rail, close the DIN rail latch. Press the DIN
rail mounting area of the module against the DIN rail. The latch will momentarily
open and lock into place.
Use DIN rail end anchors (Allen-Bradley part number 1492-EA35 or 1492-EAH35)
for environments with vibration or shock concerns.
Panel Mounting
Use the dimensional template shown below to mount the module. The preferred
mounting method is to use two M4 or #8 panhead screws per module. M3.5 or #6
panhead screws may also be used, but a washer may be needed to ensure a good
ground contact. Mounting screws are required on every module.
TIP For environments with extreme vibration and shock concerns,
use the panel mounting method described below, instead of
DIN rail mounting.
End Anchor
End Anchor
90
(3.54)
100
(3.94)
40.4
(1.59)
40.4
(1.59)
14.5
(0.57)
For more than 2 modules: (number of modules - 1) x 40.4 mm (1.59 in.)
NOTE:
Hole spacing tolerance:
±0.4 mm (0.016 in.).
MicroLogix 1200
Expansion I/O
MicroLogix 1200
Expansion I/O
MicroLogix 1200
Expansion I/O
MicroLogix 1200

8MicroLogix™ 1200 Thermocouple/mV Input Module
Publication 1762-IN013A-EN-P - April 2002
Field Wiring Connections
Grounding the Module
This product is intended to be mounted to a well-grounded mounting surface such
as a metal panel. Additional grounding connections from the module’s mounting
tabs or DIN rail (if used), are not required unless the mounting surface cannot be
grounded. Refer to Industrial Automation Wiring and Grounding Guidelines,
Allen-Bradley publication 1770-4.1, for additional information.
System Wiring Guidelines
Consider the following when wiring your system:
•Do not tamper with or remove the CJC sensor on the terminal block.
Removal of the sensor will reduce accuracy and set the open circuit bit for
the CJC sensor.
•For thermocouple inputs, always use shielded, twisted-pair thermocouple
extension lead wires specified by the thermocouple manufacturer for the
themocouple type you are using. Using an incorrect thermocouple extension
wire type or not following correct polarity convention will cause invalid
readings.
•Keep cable shield connection to ground as short as possible.
•To limit noise, keep thermocouple and millivolt signal wires as far away as
possible from power and load lines as well as other sources of electrical
noise, such as motors, transformers, contactors, and AC devices.
•If the field wiring must cross AC or power cables, ensure that they cross at
right angles.
ATTENTION
!
The possibility exists that grounded or exposed
thermocouples can become shorted to a potential greater than
that of the thermocouple itself. Due to possible shock hazard,
care should be taken when wiring these types of
thermocouples.

MicroLogix™ 1200 Thermocouple/mV Input Module 9
Publication 1762-IN013A-EN-P - April 2002
•For millivolt inputs, always use Belden™ 8761 (shielded, twisted-pair) or
equivalent wire to ensure proper operation and high immunity to electrical
noise.
•If multiple power supplies are used with millivolt analog inputs, the power
supply commons must be connected.
•Ground the shield drain wire at one end only. The typical location is the
same point as the sensor ground reference.
–For grounded thermocouples or millivolt sensors, this is at the sensor
end.
–For insulated/ungrounded thermocouples, this is at the module end.
Contact your sensor manufacturer for additional details.
•If it is necessary to connect the shield drain at the module end, connect it to
earth ground using a panel or DIN rail mounting screw.
•Routing the field wiring in a grounded conduit can further reduce electrical
noise.
Terminal Block Layout
Labeling the Terminals
A write-on label is provided with the module. Mark the identification of each
terminal with permanent ink, and slide the label back into the door.
IN1 -
IN1 +
IN 0 -
IN 0 +
IN2 -
IN2 +
CJC
CJC
IN3 -
IN3 +

10 MicroLogix™ 1200 Thermocouple/mV Input Module
Publication 1762-IN013A-EN-P - April 2002
Wiring the Finger-Safe Terminal Block
When wiring the terminal block, keep the finger-safe cover in place.
1. Route the wire under the terminal pressure plate. You can use the stripped
end of the wire or a spade lug. The terminals will accept a 6.35 mm (0.25
in.) spade lug.
2. Tighten the terminal screw making sure the pressure plate secures the wire.
Recommended torque when tightening terminal screws is 0.904 Nm (8
in-lbs).
3. After wiring is complete, remove the debris shield.
ATTENTION
!
Be careful when stripping wires. Wire fragments that fall into
a module could cause damage when power is applied. Once
wiring is complete, ensure the module is free of all metal
fragments.
TIP If you need to remove the finger-safe cover, insert a screw
driver into one of the square wiring holes and gently pry the
cover off. If you wire the terminal block with the finger-safe
cover removed, you will not be able to put it back on the
terminal block because the wires will be in the way.