Opto 22 SNAP Analog Input Modules Data Sheet

SNAP ANALOG INPUT MODULES

Features

Resolution = 0.004% of nominal range

>

Two, 4, 8, or 32 single-ended inputs per module

>>

Out-of-range indication

>

Factory calibrated; no user adjustment necessary

>

DATA SHEET

Form 1065-191230

PAGE 1

SNAP Analog Input Modules

Part Numbers

DESCRIPTION

SNAP I/O analog input modules are part of Opto 22’s
SNAP PAC System. All of these modules mount on a SNAP
PAC rack with a SNAP PAC brain or R-series controller,
either a standard wired model or a Wired+Wireless™
model.

A minimum number of SNAP module types support a full
range of analog input requirements. These
software-configurable modules handle a wide variety of
signal levels. They provide high resolution (0.004% of
nominal range) for precise signal levels, as well as
multiple-channel packaging. All SNAP analog modules
are factory calibrated and individually tested. Part
numbers ending in -FM are Factory Mutual approved.

SNAP analog input modules have an on-board
microprocessor to provide module-level intelligence,
which makes them an ideal choice for Original Equipment
Manufacturers (OEMs). For additional information about
the standalone operation of SNAP analog modules, see
Opto 22 form #0876, SNAP I/O Module Integration Guide.

Notes for legacy hardware: Some of these modules
also work with older Opto 22 I/O processors (brains or
on-the-rack controllers) and M-series or B-series racks. To
check processor compatibility, see the table on page 3.

Specifications begin on page 4. For dimensional
drawings, see pages 40–51.

IMPORTANT: Any system using analog sensors and input
modules should be calibrated annually for analog signals.
For I/O units on a SNAP PAC System, use the PAC Control™
commands “Calculate and Set Offset” and “Calculate and
Set Gain.” For other Ethernet-based I/O units, you can also
use PAC Manager™ software to calculate and set offset
and gain.

Isolation

All SNAP analog input modules are isolated from all other
modules and from the SNAP I/O processor. The modules

Part Description Page

SNAP-AIARMS 2-channel 0 to 10 amp RMS AC/DC input 4

SNAP-AIMA 2-channel analog current input, -20 to +20 mA 6

SNAP-AIMA-4 4-channel analog current input -20 to +20 mA 6

SNAP-AIMA-8 8-channel analog current input -20 to +20 mA 9

SNAP-AIMA-32
SNAP-AIMA-32-FM*

SNAP-AIRATE 2-channel 0–25,000 Hz analog rate input 13

SNAP-AIR40K-4

SNAP-AIR400K-8 8-channel analog resistor/thermistor input, 400 K Ohms 16

SNAP-AIRTD 2-channel 100 ohm platinum RTD input 20

SNAP-AIRTD-1K 2-channel 1000 ohm platinum RTD input 20

SNAP-AIRTD-10 2-channel 10 ohm copper RTD input 20

SNAP-AIRTD-8U 8-channel multifunction RTD/resistance input 22

SNAP-AICTD 2-channel analog temperature input, ICTD 25

SNAP-AICTD-4 4-channel analog temperature input, ICTD 25

SNAP-AICTD-8 8-channel analog temperature input, ICTD 27

SNAP-AITM

SNAP-AITM-2

SNAP-AITM-8
SNAP-AITM-8-FM*

SNAP-AIVRMS 2-channel 0 to 250 V RMS AC/DC input 31

SNAP-AIV

SNAP-AIV-4

SNAP-AIV-8

SNAP-AIV-32
SNAP-AIV-32-FM*

SNAP-AIMV2-4 4-channel -50 to +50 mV input or -25 to +25 mV input 37

SNAP-AIMV-4 4-channel -150 to +150 mV input or -75 to +75 mV input 38

* Factory Mutual approved

32-channel analog current input -20 to +20 mA 10

4-channel analog resistor/thermistor input, 40 K Ohms,
20 K Ohms, 10 K Ohms, or 5 K Ohms

2-channel analog type E, J, or K thermocouple or -150
to +150 mV input or -75 to +75 mV input

2-channel analog type B, C, D, G, N, T, R, or S thermo­couple or -50 to +50 mV DC or -25 to +25 mV DC input

8-channel B, C, D, E, G, J, K, N, R, S, or T thermocou­ple or -75 to +75 mV, -50 to +50 mV, or -25 to +25 mV
input

2-channel analog voltage input -10 to +10 VDC or -5 to
+5 VDC

4-channel analog voltage input -10 to +10 VDC or -5 to
+5 VDC

8-channel analog voltage input -10 to +10 VDC or -5 to
+5 VDC

32-channel analog voltage input -10 to +10 VDC or -5
to +5 VDC

15

28

30

30

32

32

34

35

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

DATA SHEET

Form 1065-191230

PAGE 2

in this data sheet do not have channel-to-channel isolation, however.
(If you need isolated analog modules, see Opto 22 form #1182.)

Transformer isolation prevents ground loop currents from flowing
between field devices and causing noise that produces erroneous
readings. Ground loop currents are caused when two grounded field
devices share a connection, and the ground potential at each device
is different.

Isolation also protects sensitive control electronics from industrial field
signals.

IMPORTANT: Since these analog input modules provide multiple
single-ended input channels with a common reference, the channels
are not isolated from each other. (See Opto 22 form #1182 for isolated
modules.)

Bipolar and Unipolar Input Modules

Most SNAP analog input modules are considered to be bipolar, which
means the range extends equal amounts above and below zero. An
example of this is the SNAP-AIV module, which has a range of -10 to
+10 VDC.

Some modules are considered unipolar, which means the range starts
or ends at zero. For example, the SNAP-AIVRMS module has a range of
0 to 250 VAC because AC current cannot be negative.

Nominal Range and Over-range Limits

All SNAP analog input modules have a nominal range for the field
signal and most support a 10% over-range limit. The nominal range is
the normal range of the field signal for the module or point
configuration. The over-range limit is the maximum valid field signal
the module or point configuration can read outside of the nominal
range. For example, the over-range limits for the SNAP-AIV are -11 and
+11 VDC, and for the SNAP-AIVRMS, the over-range limit is 275 VAC.

Some modules or point configurations do not support field signals
outside of the nominal range. For example, points configured as
temperature inputs (thermocouple, RTD, ICTD) do not support
over-range readings.

When the field signal is outside of the over-range limits of the
module, the brain will not be able to determine if the value is too high
or too low, so it will return an "out of range" value of -32768.0

Over-range limits only apply to input modules. Output modules are
limited to their nominal ranges.

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

DATA SHEET

Form 1065-191230

PAGE 3

INSTALLATION

Note module and processor compatibility in the following table:

Modules Compatible I/O Processors

32-channel inputs
8-channel inputs
SNAP-AIRTD-10
SNAP-AIRTD-1K

4-channel inputs

2-channel inputs
(except
SNAP-AIRTD-10 and
SNAP-AIRTD-1K)

All modules can be used with SNAP PAC racks and can be placed in
any position on the rack. Two- and four-channel modules (except the
SNAP-AIRTD-10 and SNAP-AIRTD-1K) can also be used with legacy
SNAP M-series and B-series mounting racks. (For more information on
using legacy hardware, see form #1688, the SNAP PAC System
Migration Technical Note.)

Modules snap securely into place in the row of connectors on the
mounting rack. Each module connector has a number. Analog input
modules and other types of SNAP I/O modules are mounted on the
module connectors starting at module position zero.

Modules require a special tool (provided) for removal.

SNAP PAC R-series controllers and SNAP
PAC brains, including Wired+Wireless mod­els

SNAP PAC R-series controllers and SNAP
PAC brains, including Wired+Wireless mod­els
Also the following legacy brains:
SNAP Ethernet, SNAP Simple, SNAP Ulti­mate; SNAP-DNP-ASDS; SNAP OEM

SNAP PAC R-series controllers and SNAP
PAC brains, including Wired+Wireless mod­els
Also the following legacy brains:
SNAP Ethernet, SNAP Simple, SNAP Ulti­mate; SNAP-DNP-ASDS; SNAP OEM; serial
SNAP brains (B3000, Modbus, Profibus);
B3000-HA; B6

The following diagram shows part of a SNAP PAC mounting rack.

Processor
connector

Module
position zero

Module connectors

Retention bar

1. Place the rack so that the module connector numbers are
right-side up, with zero on the left, as shown in the diagram
above. (If your rack has screw connectors, the screw connectors
will be at the bottom.)

2. Position the module over the module connector, aligning the
small slot at the base of the module with the retention bar on the
rack. When positioning modules next to each other, be sure to
align the male and female module keys at the tops of the
modules before snapping a module into position.

3. With the module correctly aligned, push on the module to snap it
into place.

4. Use standard 4-40 x 1/2 truss-head Phillips hold-down screws to
secure both sides of each module.

CAUTION: Do not over-tighten screws. See Specifications.

5. Follow the wiring diagrams beginning on page 4 to attach

modules to the devices they monitor. Most modules accept 22 to
14 AWG wire; the SNAP-AITM-8 accepts a maximum of two solid
18 AWG wires.

For faster, easier field wiring installation and maintenance, use
SNAP TEX cables and breakout boards. See Opto 22 form #1756, the

SNAP TEX Cables & Breakout Boards Data Sheet, for compatibility and
specifications.

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

0 TO 10 AMP RMS AC/DC INPUT MODULE

DATA SHEET

Form 1065-191230

PAGE 4

SNAP-AIARMS

Description

The SNAP-AIARMS module provides an input range of 0 to 10 amps
RMS AC/DC. An ideal input is the 5-amp secondary of a standard
current transformer used to monitor AC line current.

The SNAP-AIARMS module may be used to monitor AC current to
greater than a 100-amp range, using a current transformer of suitable
ratio.

If you need a module with channel-to-channel isolation, see form
#1182, the SNAP Isolated Analog Input Modules Data Sheet.

Wiring diagrams are on the following page.

Part Number Description

SNAP-AIARMS Two-channel 0 to 10 amp RMS AC/DC input

Specifications

Input Range 0 to 10 amp RMS AC/DC

Input Over-Range To 11 amps

Input Resistance 0.005 ohms

Maximum Input 11 amps AC/DC

Accuracy (AC) ±8 mA and ±0.2% reading

Resolution 400 microamps

DC Reversal ±16 mA (0.16%)

Input Response Time
(Step Change)

Data Freshness (Max) 32.3 ms

DC Common Mode Rejection >-120 dB

AC Common Mode Rejection >-120 dB at 60 Hz

Maximum Operating Common
Mode Voltage

Isolation 1500 V

Power Requirements 5 VDC (±0.15 V) at 170 mA

Operating Temperature -20 °C to 70 °C

Storage Temperature -40 °C to 85 °C

Humidity 5-95%, non-condensing

Wire size 22 to 14 AWG

Torque, hold-down screws 4 in-lb (0.45 N-m)

Torque, connector screws 5.26 in-lb (0.6 N-m)

Agency Approvals UL, FM, CE, RoHS, DFARS

Warranty Lifetime

63.2% (158 V) in 50 mS
99% (248 V) in 75 mS

250 V

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

0 TO 10 AMP RMS AC/DC INPUT MODULE (CONTINUED)

SNAP-AIARMS Wiring Diagrams

Two possible wiring diagrams are shown below.

* Terminals 3, 4, 7, and 8 share a common
connection inside the module. Make sure
you observe polarity when connecting the
second channel. To avoid a potentially
hazardous short, double-check wiring before
turning on the current to be monitored.

DATA SHEET

Form 1065-191230

PAGE 5

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

CURRENT INPUT MODULE, -20 mA TO +20 mA, TWO OR FOUR CHANNELS

DATA SHEET

Form 1065-191230

PAGE 6

SNAP-AIMA and SNAP-AIMA-4

Description

The SNAP-AIMA and SNAP-AIMA-4 modules provide an input range of

-20mA to +20mA. The SNAP-AIMA has two channels, and the
SNAP-AIMA-4 has four. If you need a similar module with more
channels, see page 10. Check the table on page 3 for I/O processor
compatibility. These modules DO NOT supply loop excitation current.

Since all inputs share a common reference, the module must be
installed at the beginning or end of a typical 4–20mA loop. If you are
using both standard and self-sourcing transmitters, either put the
transmitters on different modules or use different power supplies. If
you need channels that are isolated from each other on the same
module, see Opto 22 form #1182.

Wiring diagrams are on the following page.

Part Number Description

SNAP-AIMA

SNAP-AIMA-4

Two-channel analog current input,

-20 mA to +20 mA

Four-channel analog current input,

-20 mA to +20 mA

Specifications

Input Range -20 mA to +20 mA

Resolution 0.8 microamps

Over-Range Limits

Input Response Time
(% of span/ delta I/delta tme)

Data Freshness (Max)

DC Common Mode Rejection >-120 dB

AC Common Mode Rejection >-120 dB @ 60 Hz

Maximum Survivable Input 36 mA or 9 VDC

Maximum Operating Common
Mode Voltage

Accuracy 0.05% (10 microamps)

DRIFT: Gain Temperature
Coefficient

DRIFT: Offset Temperature
Coefficient

Power Requirements 5 VDC (±0.15 ) @ 170 mA

Input Resistance - Single
Ended

Operating Temperature -20 °C to 70 °C

Storage Temperature -40 °C to 85 °C

Humidity 5-95%, non-condensing

Torque, hold-down screws 4 in-lb (0.45 N-m)

Torque, connector screws 5.26 in-lb (0.6 N-m)

Wire size 22 to 14 AWG

Agency Approvals

Warranty Lifetime

From -22 to +22 mA
(+/-20 mA range)

99.9% / 19.9 mA / 10 ms

SNAP-AIMA: 11.5 ms
SNAP-AIMA-4: 23 ms

250 V

30 PPM/ °C

15 PPM/ °C

200 ohms (each channel)

UL, FM, CE, RoHS, DFARS
ATEX (SNAP-AIMA-4 only)

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

DATA SHEET

Form 1065-191230

PAGE 7

CURRENT INPUT MODULE, -20 MA TO +20 MA, TWO OR FOUR CHANNELS (CONTINUED)

SNAP-AIMA Wiring (Two channels)

SNAP-AIMA-4 Wiring (Four channels)

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

DATA SHEET

Form 1065-191230

PAGE 8

CURRENT INPUT MODULE, -20 mA TO +20 mA, TWO OR FOUR CHANNELS (CONTINUED)

SNAP-AIMA Wiring: Positive Common vs. Negative Common Connections

The following diagrams apply to SNAP-AIMA-2, SNAP-AIMA-4, and SNAP-AIMA-8 modules.

NOTE: Even-numbered terminals share a
common reference where applicable.

SNAP-AIMA

For transmitters sharing the plus side of the loop
supply. Note that input current will be read as a
positive current.

NOTE: Even-numbered terminals share a
common reference where applicable.

SNAP-AIMA

For transmitters sharing the minus side of the loop
supply. Note that input current will be read as a
negative current.

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

CURRENT INPUT MODULE, -20 mA TO +20 mA, EIGHT CHANNELS

DATA SHEET

Form 1065-191230

PAGE 9

SNAP-AIMA-8

Description

The SNAP-AIMA-8 module provides an input range of -20mA to
+20mA with eight channels of analog current input. (If you need a
similar module with 32 channels, see page 10.) The SNAP-AIMA-8 can
be used with SNAP PAC brains and rack-mounted controllers only.
These modules DO NOT supply loop excitation current.

Since all inputs share a common reference, the module must be
installed at the beginning or end of a typical 4–20mA loop. If you are
using both standard and self-sourcing transmitters, either put the
transmitters on different modules or use different power supplies. If
you need channels that are isolated from each other on the same
module, see Opto 22 form #1182.

If you have multiple self-sourcing transmitters that share the same
positive common, do not use this module. Use the SNAP-AIMA-i
module instead. See Opto 22 form #1182.

Current Source

4-20 self-powered
(self-sourcing) transmitters

T

T TT

23 45 67 8

2

1

NOTE: Terminals 2, 4, 6, and 8 on both
connectors are connected internally.

CH 2CH 1CH 0 CH 3

8

7

6

5

4

3

2

1

3

CH 4

T

8

7

6

5

4

CH 5

T

CH 6

T

CH 7

T

OR

Part Number Description

SNAP-AIMA-8

Eight-channel analog current input, -20 mA to
+20 mA

Specifications

Input Range -20 mA to +20 mA

Over-Range Limits

Resolution 0.8 microamps

Data Freshness (Max) 0.28 seconds

DC Common Mode Rejection >-120 dB

AC Common Mode Rejection >-120 dB @ 60 Hz

Maximum Survivable Input 36 mA or 9 VDC

Maximum Operating Common
Mode Voltage

Accuracy 0.05% (10 microamps)

DRIFT: Gain Temperature
Coefficient

DRIFT: Offset Temperature
Coefficient

Isolation 1500 V

Power Requirements 5 VDC (±0.15 ) @ 170 mA

Input Resistance - Single
Ended

Operating Temperature -20 °C to 70 °C

Storage Temperature -40 °C to 85 °C

Humidity 5-95%, non-condensing

Torque, hold-down screws 4 in-lb (0.45 N-m)

Torque, connector screws 1.7 in-lb (0.19 N-m)

Agency Approvals CE, RoHS, DFARS

Warranty Lifetime

From -22 to +22 mA
(+/-20 mA range)

250 V

30 PPM/ °C

15 PPM/ °C

100 ohms (all channels share
the same reference point)

External loop
power supply

NOTE: For transmitters sharing the plus side of the loop power supply, the
input current will be read as a positive current.

See additional wiring diagrams on page 8.

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

CURRENT INPUT MODULE, -20 MA TO +20 MA, 32 CHANNELS

DATA SHEET

Form 1065-191230

PAGE 10

SNAP-AIMA-32 and SNAP-AIMA-32-FM

Description

The SNAP-AIMA-32 and SNAP-AIMA-32-FM modules provide 32
channels of input with an input range of -20mA to +20mA. The
SNAP-AIMA-32-FM is Factory Mutual approved. Check the table on

page 3 for I/O processor compatibility. Dimensional drawings are on
page 45.

These modules DO NOT supply loop excitation current.

Channels are not isolated from each other. Since all inputs share a
common reference, the module must be installed at the beginning or
end of a typical 4–20 mA loop. If you use both standard and
self-sourcing transmitters, put the transmitters on different modules
or use different power supplies. (If you need channels that are isolated
from each other on the same module, see Opto 22 form #1182.)

Part Number Description

SNAP-AIMA-32
SNAP-AIMA-32-FM

SNAP-HD-BF6

SNAP-AIMA-HDB
SNAP-AIMA-HDB-FM

32-channel analog current input,

-20 mA to +20 mA

Wiring harness for SNAP-AIMA-32 modules
and breakout racks

Breakout racks for SNAP-AIMA-32 and
SNAP-AIMA-32-FM

Specifications

Input Range -20 mA to +20 mA

Over-Range Limits

Resolution 0.8 microamps

Input Filtering -3 dB @ 31 Hz

Data Freshness (Max) 1.15 s

DC Common Mode Rejec­tion

AC Common Mode Rejec­tion

Maximum Survivable Input 36 mA or 9 VDC

Maximum Operating Com­mon Mode Voltage

Accuracy 0.1% (20 microamps)

DRIFT: Gain Temperature
Coefficient

DRIFT: Offset Temperature
Coefficient

Isolation 1500 V, field to logic

Power Requirements 5 VDC (±0.15 ) @ 150 mA

Input Resistance - Single
Ended

Operating Temperature -20 °C to 70 °C

Storage Temperature -40 °C to 85 °C

Humidity 5-95%, non-condensing

Torque, hold-down screws 4 in-lb (0.45 N-m)

Torque, connector screws 5.26 in-lb (0.6 N-m)

Agency Approvals

Warranty Lifetime

From -22 to +22 mA
(+/-20 mA range)

>-120 dB

>-120 dB @ 60 Hz

250 V

30 PPM/ °C

15 PPM/ °C

100 ohms (each channel)

SNAP-AIMA-32: UL, CE, RoHS,
DFARS.
SNAP-AIMA-32-FM: CE, FM,
RoHS, DFARS

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

DATA SHEET

Form 1065-191230

PAGE 11

Wiring

SNAP TEX cables and a breakout rack are available separately for
wiring points to field devices (see form #1756, the SNAP TEX Cables &
Breakout Boards Data Sheet). The SNAP-HD-BF6 cable connects the
module to the breakout rack, which can then be wired to field
devices. (NOTE: The SNAP-HD-CBF6 wiring harness with flying leads is
not recommended for this module.)

CAUTION: We strongly recommend that you use the breakout rack
with these modules. Miswiring of any point on the module can cause
severe out-of-warranty damage. The breakout rack protects the
module from many wiring errors.

if you are using the module with loop power (2-wire) negative
common devices, connect to the SNAP-AIMA-HDB (or -FM) rack. If you
are using the module with self-powered devices (4-wire) or with
devices that share a common positive connection, do not use the
SNAP-AIMA-HDB (or -FM) boards, which have a current limiting diode.
Instead, wire to the SNAP-AIV-HDB or SNAP-AIV-HDB-FM.

Correcting for Inverted Scaling

Positive readings for these modules appear as negative values.
Therefore, in order to obtain meaningful readings, use the scaling
feature in PAC Control as follows:

1. In the Add or Edit Analog Point dialog box for each point, choose
the scalable version of the module.

2. Under Scaling, scale each point negatively as shown below:

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

CURRENT INPUT MODULE, -20 mA TO +20 mA, 32 CHANNELS (CONTINUED)

Wiring diagram: SNAP-AIMA-HDB breakout rack to SNAP-AIMA-32 module

NOTE: This diagram also applies to the SNAP-AIMA-HDB-FM rack and the SNAP-AIMA-32-FM module.

Use with loop power (2-wire) negative common devices only.
For self-powered (4-wire) devices, see page 36.
For positive common devices, see page 39.

DATA SHEET

Form 1065-191230

PAGE 12

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

0 TO 25,000 Hz ANALOG RATE INPUT MODULE

DATA SHEET

Form 1065-191230

PAGE 13

SNAP-AIRATE

Description

The SNAP-AIRATE module provides two channels of
frequency-to-digital conversion. The nominal input range is 0 to
25,000 Hz with an over-range capability to 27,500 Hz. Nine volts
through a 4.7 K ohm pull-up resistor are provided internally for use
with devices that have open collector outputs. This feature eliminates
the need for the user to provide the pull-up voltage supply and
associated wiring, barrier strips, etc.

The module works with TTL, CMOS, and open collector outputs. Truly
a two-wire hookup, the SNAP-AIRATE module is ideally suited for use
with a tachometer.

Please note that this module does not provide channel-to-channel
isolation. If you need isolated channels, see the SNAP Isolated Analog

Input Modules Data Sheet, form 1182.

Number Description

SNAP-AIRATE 0–25,000 Hz analog rate input

Specifications

Nominal Input Range 0 to 25,000 Hz

Input Over-Range To 27,500 Hz

Resolution 1 Hz

Input Response Time(% of
span / delta Hz / delta time)

Data Freshness (Max) 126 ms

DC Common Mode Rejection > -120 dB

AC Common Mode Rejection > -120 dB at 60 Hz

Maximum Operating Common
Mode Voltage

Accuracy (% full scale)

Drift: Gain Temperature Coeffi­cient

Drift: Offset Temperature Coef­ficient

Input Coupling

Input Amplitude
Sine wave
Square wave

Minimum Pulse Width 18 microseconds

Input Impedance (Inputs share
the same reference point.)
Pull-up Voltage
Pull-up Resistor

Isolation 1500 V

Power Requirements 5 VDC (±0.15 V) at 190 mA

Operating Temperature -20 °C to 70 °C

Storage Temperature -40 °C to 85 °C

Humidity 5-95%, non-condensing

Wire size 22 to 14 AWG

Torque, hold-down screws 4 in-lb (0.45 N-m)

Torque, connector screws 5.26 in-lb (0.6 N-m)

Agency Approvals UL, FM, CE, RoHS, DFARS

Warranty Lifetime

10.0% / 2,500 Hz / 0.1 sec

63.2% / 15.8 K Hz / 0.9 sec

99.0% / 24.75 K Hz / 4.2 sec

250 V

±4 Hz or ±0.5% of the input fre­quency (whichever is greater)

200 ppm / °C

50 ppm / °C

Single-ended AC (capacitor
coupled)

2.5 V to 24 V p-p

0.5 V to 24 V p-p

50 K ohms AC coupled
(-input to +input)
6 to 9 V

4.7 K ohms

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

0 TO 25,000 Hz ANALOG RATE INPUT MODULE (CONTINUED)

NAP-AIRATE Wiring Diagrams

DATA SHEET

Form 1065-191230

PAGE 14

NOTE: This module does not provide channel-to-channel isolation.

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

THERMISTOR INPUT MODULE 0–40 K, 0–20 K, 0–10 K, OR 0–5 K OHM

DATA SHEET

Form 1065-191230

PAGE 15

SNAP-AIR40K-4

Description

The SNAP-AIR40K-4 module provides four channels of analog to
digital conversion, ideal for thermistors used in HVAC applications or
for reading the resistance of potentiometer input. See the table on

page 3 for I/O processor compatibility.

The default input range is 0 to 40 K Ohms. The module can also be
configured for 0 to 20 K, 0 to 10 K, or 0 to 5 K Ohms.

NOTE: Resistance probes must be isolated from each other.

IMPORTANT: The mounting rack connector has 24 pins; the module
connector has 20 pins. The extra pins on the mounting rack
connector prevent misalignment of the module during installation.

Part Number Description

SNAP-AIR40K-4

Four-channel analog resistor/thermistor input, 40 K
Ohms, 20 K Ohms, 10 K Ohms, or 5 K Ohms

Specifications

0 to 40,000 Ohms

Input Range

Maximum Over-Range

Resolution

Input Filtering -3 dB @ 3.2 Hz

Data Freshness (Max)

DC Common Mode Rejection >-120 dB

AC Common Mode Rejection >-120 dB @ 60 Hz

Maximum Operating
Common Mode Voltage

Accuracy

DRIFT: Gain Temperature
Coefficient

DRIFT: Offset Temperature
Coefficient

Isolation 1500 V

Power Requirements 5 VDC (±0.15 ) @ 190 mA

Operating Temperature -20 °C to 70 °C

Storage Temperature -40 °C to 85 °C

Humidity 5-95%, non-condensing

Wire size 22 to 14 AWG

Torque, hold-down screws 4 in-lb (0.45 N-m)

Torque, connector screws 5.26 in-lb (0.6 N-m)

Agency Approvals UL, FM, CE, RoHS, DFARS

Warranty Lifetime

0 to 20,000 Ohms
0 to 10,000 Ohms
0 to 5,000 Ohms

44 K (40 K Ohms range)
22 K (20 K Ohms range)
11 K (10 K Ohms range)

5.5 K (5 K Ohms range)

1.6 Ohm @ 40 K Ohms

0.8 Ohm @ 20 K Ohms

0.4 Ohm @ 10 K Ohms

0.2 Ohm @ 5 K Ohms

100 (40 K Ohms)
200 (20 K Ohms)
400 (10 K Ohms)
800 (5 K Ohms)

250 V

0.1% ± 40 Ohms @ 40 K Ohms

0.1% ± 20 Ohms @ 20 K Ohms

0.1% ± 10 Ohms @ 10 K Ohms

0.1% ± 5 Ohms @ 5 K Ohms

30 PPM/ °C

15 PPM/ °C

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.

DATA SHEET

Form 1065-191230

THERMISTOR INPUT MODULE 0–400 K, 0–200 K, 0–100 K, 0–50 K, 0–40 K, 0–20 K,
0–10 K, 0–5 K, 0–4 K, 0–2 K, 0–1 K, 0–500 OHM

PAGE 16

SNAP-AIR400K-8

Description

The SNAP-AIR400K-8 module has eight channels of analog to digital
conversion that convert resistance to temperature or to Ohms. The
module is ideal for NTC thermisters commonly used in HVAC,
refrigeration, and process control applications. It may also be used
with PTC thermisters in resistance sensing applications. See the table
on page 3 for I/O processor compatibility.

The SNAP-AIR400K-8 reads variable resistance type transducers, and it
has 12 resistance input ranges from 500 Ohms to 400 K Ohms, plus
Autorange. Range dependent resolution is from 20 milliOhms to 16
Ohms.

SNAP PAC brains and PAC Control provide direct temperature readings
for four popular thermistors using the Steinhart-Hart equation (see

page 19). You may also enter custom coefficients for other thermistor

curves.

The simple two-wire connections are made to the pluggable terminal
strip on top of the module.

NOTE: The eight input channels must be electrically isolated from each
other and earth ground. The transducer resistor element must be isolated
from any electrically conducting probe tube housing.

Part Number Description

Eight channel analog resistor/thermistor input,
400 K Ohms, 200 K Ohms,

SNAP-AIR400K-8

100 K Ohms, 50 K Ohms, 40 K Ohms,
20 K Ohms, 10 K Ohms, 5 K Ohms,
4 K Ohms, 2 K Ohms, 1 K Ohms, 500 Ohms

Wiring Information

Unshielded 24 AWG wire (minimum) is recommended.

See page 17 for module specifications.

NTC thermistor

Variable resistance device

IMPORTANT: The mounting rack connector has 24 pins; the module
connector has 20 pins. The extra pins on the mounting rack
connector prevent misalignment of the module during installation.

© 2001–2019 Opto 22. All rights reserved. Dimensions and specifications are subject to change. Brand or product names used herein are trademarks or registered trademarks of their respective companies or organizations.