SNAP Analog Input Modules

Opto 22 • 43044 Business Park Drive • Temecula, CA 92590-3614 • www.opto22.com

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Thermocouple/Millivolt Input Module

Specifications

Part Number

Description

SNAP-AITM-8

SNAP-AITM-8-FM

8-channel B, C, D, E, G, J, K, N, R, S,

or T thermocouple or -75 mV to

+75 mV, 50 mV to +50 mV, or 25 mV

to +25 mV input

Input Range

From -75 mV to +75 mV

From -50 mV to +50 mV

From -25 mV to +25 mV

Over-Range Limits

From -82.5 to +82.5 mV (+/-75 mV range)

From -55 to +55 mV (+/-50 mV range)

From -27.5 to +27.5 mV (+/-25 mV range)

Resolution

3 microvolts from -75 mV to +75 mV

2 microvolts from -50 mV to +50 mV

1 microvolts from -25 mV to +25 mV

Cold Junction Temperature

Compensation

Automatic when used with SNAP I/O

processors

Input Filtering

-3 dB @ 5 Hz

Data Freshness (Max)

2.25 s

DC Common Mode

Rejection

>-120 dB

AC Common Mode

Rejection

>-120 dB @ 60 Hz

Maximum Survivable Input

±15 volts

Max Operating Common

Mode Voltage

250 V

Accuracy at Full Scale

0.1% (75 microvolts) @ 75 mV

0.1% (50 microvolts) @ 50 mV

0.2% (50 microvolts) @ 25 mV

Drift: Gain Temperature

Coefficient

5 microvolts / °C

Drift: Offset Temperature

Coefficient

2 microvolts / °C

Thermocouple Accuracy [°C]

E, J, K

B, R, S

C, D, G

T, N

From factory

±2.0

±5

±4

±3

After user gain and offset

commands

±0.5

±3

±2

±2

Isolation

1500 V

Power Requirements

5 VDC (±0.15) @ 200 mA

Input Resistance

100 Megohms (each channel)

Ambient Temperature:

Operating

Storage

0 °C to 70 °C

-40 °C to 85 °C

Torque, hold-down screws

4 in-lb (0.45 N-m)

Torque, connector screws

3 in-lb (0.34 N-m)

Agency Approvals

SNAP-AITM-8: UL, CE, RoHS, DFARS

SNAP-AITM-8-FM: FM, CE, RoHS,

DFARS

Warranty

Lifetime

SNAP-AITM-8 and SNAP-AITM-8-FM

Thermocouple Polarity and Range

Type

-

+

Range

B

RED

GRAY

+42° C to +1,820 °C

C, D, G

RED

WHITE

0° C to +2,320 °C

E

RED

PURPLE

-270°C to +1,000 °C

J

RED

WHITE

-210°C to +1,200 °C

K

RED

YELLOW

-270°C to +1,372 °C

N

RED

ORANGE -270° C to +1,300 °C

R, S

RED

BLACK

-50° C to +1,768 °C

T

RED

BLUE

-270° C to +400 °C

NOTE: For best accuracy, wire all points before

calibrating, and short all unused channels.

The SNAP-AITM-8-FM is Factory Mutual approved.

Millivolt Thermocouple Source

+

+ – –

+

+ ––

+

+ – –

+

+ ––

Common terminals are connected internally.

Description

The SNAP-AITM-8 and SNAP-AITM-8-FM modules

provide eight channels of analog to digital conversion.

Each channel on the module can be configured for -75

mV DC to +75 mV DC, -50 mV DC to +50 mV DC, -25

mV DC to +25 mV DC, or for type B, C, D, E, G, J, K, N, R,

S or T thermocouple operation.

Since all inputs share the same reference terminal, use

isolated probes for thermocouple inputs. See the

dimensional diagram on page 37.