National Instruments FIeldPoint FP-AO-200 User manual

323343A-01 October 2002
©2002 National Instruments Corp. All rights reserved.
FieldPoint™, National Instruments™, NI™, and ni.com™ are trademarks of National Instruments Corporation.
Product and company names mentioned herein are trademarks or trade names of their respective companies.
For patents coveringNational Instruments products,refer to the appropriate location: Help»Patents in your software,
the patents.txt file on your CD, or ni.com/patents.
FieldPoint Operating Instructions
FP-AO-200 AND CFP-AO-200
Eight-Channel 20 mA Loop Output Modules
These operating instructions describe how to install and use the
National Instruments FP-AO-200 and cFP-AO-200 analog output
modules (referred to inclusively as the [c]FP-AO-200). For
information about configuring and accessing the [c]FP-AO-200
over a network, refer to the user manual for the FieldPoint network
module you are using.
Features
The [c]FP-AO-200 is a FieldPoint analog output module with the
following features:
• Eight 0–20 or 4–20 mA outputs
• 0.5 mA overranging
• 12-bit resolution
• Up to 1 kΩload impedance (with 24 V loop supply)
• Indicators for open current loops
• Short-circuit protection
• 2,300 Vrms transient overvoltage protection between the
inter-module communication bus and the I/O channels
• –40 to 70 °C operation
• Hot plug-and-play

FP-AO-200 and cFP-AO-200 2 ni.com
Installing the FP-AO-200
The FP-AO-200 mounts on a FieldPoint terminal base (FP-TB-x).
Hot plug-and-play enables you to install the FP-AO-200 onto a
powered terminal base without disturbing the operation of other
modules or terminal bases. The FP-AO-200 receives operating
power from the terminal base. Current loop power is externally
supplied.
To install the FP-AO-200, refer to Figure 1 and complete the
following steps:
1. Slide the terminal base key to either position X (used for any
module) or position 2 (used for the FP-AO-200 module).
2. Align the FP-AO-200 alignment slots with the guide rails on
the terminal base.
3. Press firmly to seat the FP-AO-200 in the terminal base. The
terminal base latch locks the FP-AO-200 into place when it is
firmly seated.
4. Connect a current loop supply for the outputs to the V and C
terminals of the terminal base.
Figure 1. Installing the FP-AO-200
Installing the cFP-AO-200
The cFP-AO-200 mounts on a Compact FieldPoint backplane
(cFP-BP-x). Hot plug-and-play enables you to install the
cFP-AO-200 onto a powered backplane without disturbing the
operation of other modules or connector blocks. The cFP-AO-200
receives operating power from the backplane.
Alignment
Slot
Key
Latch
Guide Rails
Terminal BaseI/O Module

© National Instruments Corp. 3 FP-AO-200 and cFP-AO-200
To install the cFP-AO-200, refer to Figure 2 and complete the
following steps:
1. Align the captive screws on the cFP-AO-200 with the holes on
the backplane. The alignment keys on the cFP-AO-200 prevent
backward insertion.
2. Press firmly to seat the cFP-AO-200 on the backplane.
3. Using a number 2 Phillips screwdriver with a shank of at least
64 mm (2.5 in.) length, tighten the captive screws to 1.1 N ⋅m
(10 lb ⋅in.) of torque. The nylon coating on the screws prevents
them from loosening.
Figure 2. Installing the cFP-AO-200
1 cFP Backplane
2 cFP Controller Module
3cFP-AO-200
4 Captive Screws
5 Screw Holes
4
4
3
2 1
5
5

FP-AO-200 and cFP-AO-200 4 ni.com
Wiring the [c]FP-AO-200
The FP-TB-xterminal base provides connections for the eight
output channels of the FP-AO-200. The cFP-CB-xconnector block
provides the same connections for the cFP-AO-200.
Table 1 lists the terminal assignments for the signals associated
with each channel.
Each channel has an output terminal, Iout; a common terminal,
COM; and a supply terminal, Vsup. The COM terminals of all
the channels are connected internally to each other and to the
C terminals, and the Vsup terminals are all connected to each other
and to the V terminals. Refer to the sections that follow for detailed
wiring instructions.
Sourcing Current to a Load
The [c]FP-AO-200 sources current from an external loop supply to
a load. The [c]FP-AO-200 can operate with an external loop supply
from 5 to 24 VDC. The voltage from the external supply
determines the maximum load impedance that the [c]FP-AO-200
can drive. With a 24 VDC loop supply, each output can drive up to
1kΩof load impedance. With a 5 VDC loop supply, each output
can only drive up to 100 Ω. The [c]FP-AO-200 detects and reports
error conditions due to excessive loads or insufficient loop
supplies. For more information, refer to the Open-Loop Detection
section.
Table 1. Terminal Assignments
Channel
Terminal Numbers
Iout COM Vsup
0 1 2, 18 17
1 3 4, 20 19
2 5 6, 22 21
3 7 8, 24 23
4 9 10, 26 25
5 11 12, 28 27
6 13 14, 30 29
7 15 16, 32 31

© National Instruments Corp. 5 FP-AO-200 and cFP-AO-200
The [c]FP-AO-200 updates the output channels as new values are
sent to it by the network module. The time it takes to respond to a
change on a single channel is between 3 and 6 ms. The response
time to changes on all eight channels is 24 to 27 ms.
Figure 3 shows the current output circuit of a single channel.
Figure 3. [c]FP-A0-200 Current Output Circuit
Figure 4 shows how to connect loads to two channels of the
[c]FP-AO-200.
Figure 4. Connecting to Two Channels
Iout
Vsup
COM
COM
Current
Sense
V
C
Open Loop
Indicator
12-Bit
Isolated DAC
Loop
Supply
VC
Load
Iout
COM
Load
Iout
COM
+
–
[c]FP-AO-200

FP-AO-200 and cFP-AO-200 6 ni.com
Using an external COM connection may be more convenient in
your application than using the COM and C terminals on the
terminal base or connector block. Figure 5 shows how to connect
to two channels using an external COM connection.
Figure 5. Connecting to Two Channels Using an External COM Connection
Output Ranges
You can configure each channel independently for an output range
of either 0–20 mA or 4–20 mA. The default power-up setting for
each channel is 0–20 mA, with the output set to 0 mA. The
[c]FP-AO-200 has overranging of 0.5 mA in each of these ranges,
so that the actual full-scale ranges available are 0–20.5 mA and
3.5–20.5 mA. Overranging enables the [c]FP-AO-200 to
compensate for span and offset errors in field devices.
Open-Loop Detection
Each channel has a monitoring circuit that compares the actual
output current to the specified output current. If the [c]FP-AO-200
cannot source the specified output current for one or more
channels, the monitoring circuits turn on a red STATUS LED for
each affected channel and report the error condition to the network
module. Generally, the error condition is caused by an open current
loop—either the load device or the loop supply is disconnected.
However, the monitoring circuit also detects errors caused by load
impedances that are too high and by loop supply voltages that are
too low.
If the output of a [c]FP-AO-200 channel is set to 0 mA, the
monitoring circuit does not register an error condition because the
Loop
Supply
V
Load
Load
Iout
COM
Iout
COM
C+
–
[c]FP-AO-200

© National Instruments Corp. 7 FP-AO-200 and cFP-AO-200
[c]FP-AO-200 can always source zero current, even to an open
loop. Leave any unused and unwired channels in the default state
so that they do not generate error conditions.
Short-Circuit Protection
Each Iout terminal of the [c]FP-AO-200 is protected against short
circuits to any of the other terminals. One or more channel outputs
can be short-circuited indefinitely without causing damage or
improper operation of other channels, as long as the maximum
loop supply does not exceed 24 VDC. The outputs can withstand
indefinite short circuits with loop supplies of more than 24 VDC
(up to 36 VDC) without damage, but increasing internal
temperatures due to such conditions may cause improper operation
of other channels on the module.
Status Indicators
Figure 6 shows the [c]FP-AO-200 status indicators.
Figure 6. Status Indicators
The [c]FP-AO-200 has two green status LEDs, POWER and
READY. After you insert the [c]FP-AO-200 into a terminal base or
backplane and apply power to the connected network module, the
green POWER indicator lights and the [c]FP-AO-200 informs the
network module of its presence. When the network module
recognizes the [c]FP-AO-200, it sends initial configuration
information to the [c]FP-AO-200. After receiving this initial
information, the green READY indicator lights and the
[c]FP-AO-200 is in normal operating mode.
In addition to the green POWER and READY indicators, each
channel has a red, numbered error status indicator. For more
information, refer to the Open-Loop Detection section.
Upgrading the FieldPoint Firmware
You may need to upgrade the FieldPoint firmware when you add
new I/O modules to the FieldPoint system. For information on
determining which firmware you need and how to upgrade, go to
ni.com/info and enter fpmatrix.

FP-AO-200 and cFP-AO-200 8 ni.com
Isolation and Safety Guidelines
Caution Read the following information before
attempting to connect the [c]FP-AO-200 to any circuits
that may contain hazardous voltages.
This section describes the isolation of the [c]FP-AO-200 and its
compliance with international safety standards. The field wiring
connections are isolated from the backplane and the inter-module
communication bus. The isolation is provided by the module,
which has optical and galvanic isolation barriers designed and
tested to protect against transient fault voltages of up to 2,300 Vrms.
Follow these guidelines to ensure a safe total system:
• The [c]FP-AO-200 has a safety isolation barrier between the
I/O channels and the inter-module communication bus. There
is no isolation between channels unless otherwise noted. If any
of the channels on a module are wired at a hazardous potential,
make sure that all other devices or circuits connected to that
module are properly insulated from human contact.
•Donot share the external supply voltages (the V and C
terminals) with other devices (including other FieldPoint
devices), unless those devices are isolated from human contact.
• For Compact FieldPoint, you must connect the protective earth
(PE) ground terminal on the cFP-BP-xbackplane to the system
safety ground. The backplane PE ground terminal has the
following symbol stamped beside it: . Connect the
backplane PE ground terminal to the system safety ground
using 14 AWG (1.6 mm) wire with a ring lug. Use the 5/16 in.
panhead screw shipped with the backplane to secure the ring
lug to the backplane PE ground terminal.
• As with any hazardous voltage wiring, make sure that all
wiring and connections meet applicable electrical codes and
commonsense practices. Mount terminal bases and backplanes
in an area, position, or cabinet that prevents accidental or
unauthorized access to wiring that carries hazardous voltages.
• Operate the [c]FP-AO-200 only at or below Pollution
Degree 2. Pollution Degree 2 means that only nonconductive
pollution occurs in most cases. Occasionally, however, a
temporary conductivity caused by condensation must be
expected.

© National Instruments Corp. 9 FP-AO-200 and cFP-AO-200
• Refer to the FieldPoint product label for regulatory
certification under hazardous location standards. If the
FieldPoint product is not certified for operation in hazardous
locations, do not operate it in an explosive atmosphere or
where there may be flammable gases or fumes.
Specifications
These specifications are typical for the range –40 to 70 °C unless
otherwise noted.
Output Characteristics
Number of channels .........................8 single-ended
Resolution ........................................12 bits, 1 in 4,096
(~6 µA/bit)
Current Output
Output range ..................................... 0–20 or 4–20 mA,
programmable (0–20.5
or 3.5–20.5 mA with
overranging)
Type .................................................. Current source, external loop
power required
External loop power.......................... 5–24 VDC
Internal voltage drop.........................3 V
Resistive load....................................Up to 1 kΩwith 24 V
loop supply, up to 100 Ω
with 5 V supply1
Protection.......................................... Short-circuit and
open-circuit
Default power-up state...................... 0 mA
Accuracy
Absolute accuracy.............................0.1% typ, 0.3% max
(calculated as a percentage
of full-scale reading)
1 Maximum load resistance = (Supply voltage – Internal voltage drop)/0.0205 A

FP-AO-200 and cFP-AO-200 10 ni.com
Monotonicity1...................................Guaranteed over operating
temperature range
Offset temperature coefficient .......... 50 nA/°C
Gain temperature coefficient ............ 40 ppm/°C
Dynamic Characteristics
Max conversion rate..........................200 updates/s
Slew rate ...........................................0.4 mA/µs
Physical Characteristics
Indicators .......................................... Green POWER and
READY indicators, 8 red
open-loop indicators
Weight
FP-AO-200 ................................. 140 g (4.8 oz)
cFP-AO-200 ............................... 110 g (3.7 oz)
Power Requirements
Power from network module ............ 350 mW
Isolation Voltage
Channel-to-channel isolation............No isolation between
channels
Transient overvoltage........................ 2,300 Vrms
Environmental
FieldPoint modules are intended for indoor use only. For outdoor
use, FieldPoint modules must be mounted inside a sealed
enclosure.
Operating temperature ......................–40 to 70 °C
Storage temperature..........................–55 to 100 °C
Humidity ........................................... 10 to 90% RH,
noncondensing
Maximum altitude.............................2,000 m
Pollution Degree .............................. 2
1 A characteristic of a DAC in which the analog output always increases as the value
of the digital code input to it increases.