Manual

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Publication 1794-6.5.7 – March 1997 T emplate revised June 23, 1995
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Specifications
1
– 1794-IT8 Thermocouple/mV Input Module
Number of Inputs 8 Channels
Module Location Cat. No. 1794-TB2, -TB3 and -TB3T Terminal Base Units
2
Nominal Input Voltage Ranges +76.5mV
Supported Thermocouple Types Type B: 300 to 1800
o
C (572 to 3272
o
F)
Type C: 0 to 2315
o
C (32 to 4199
o
F)
Type E: –230 to 1000
o
C (–382 to 1832
o
F)
Type J: –195 to 1200
o
C (–319 to 2192
o
F)
Type K: –230 to 1372
o
C (–382 to 2502
o
F)
Type N: –270 to 1300
o
C (–450 to 2372
o
F)
Type R: –50 to 1768
o
C (–58 to 3214
o
F)
Type S: –50 to 1768
o
C (–58 to 3214
o
F)
Type T: –195 to 400
o
C (–319 to 752
o
F)
Type L: –175 to 800
o
C (–283 to 1472
o
F)
Resolution 16 bits (2.384 microvolts typical)
Accuracy with fixed digital filter
(at 24
o
C (+0.5
o
C))
0.025% Full Scale Range +0.5
o
C
Accuracy without fixed digital filter
(at 24
o
C (+0.5
o
C))
0.05% Full Scale Range +0.5
o
C
Data Format 16-bit 2’s complement or offset binary (unipolar)
Normal Mode Noise Rejection –60db @ 60Hz
Common Mode Rejection –115db @ 60Hz; –100db @ 50Hz
Common Mode Input Range +10V
Channel to Channel Isolation
+10V
System Throughput 325ms (1 channel scanned), programmable to 28ms
2.6s (8 channels scanned), programmable to 224ms
Settling Time to 100% of final value Available at system throughput rate
Open Circuit Detection Out of range reading (upscale)
Open Thermocouple Detection Time Available at system throughput rate
Overvoltage Capability 35V dc, 25V ac continuous @ 25
o
C
250V peak transient
Channel Bandwidth 0 to 2.62Hz (–3db) default
RFI Immunity Error of less than 1% of range at 10V/M
27 to 1000MHz
Input Offset Drift with Temperature +6 microvolts/
o
C maximum
Gain Drift with Temperature 10ppm/
o
C maximum
Overall Drift with Temperature 50ppm/
o
C of span (maximum)
Cold Junction Compensation Range 0 to 70
o
C
Cold Junction Compensator A-B Part Number 969424–01
Indicators 1 red/green power status indicator
Flexbus Current 20mA
Power Dissipation 3W maximum @ 31.2V dc
Specifications continued on next page.