Technical data

Publication 1794-2.1 - January 2000
FLEX I/O and FLEX Integra Product Data
24V dc RTD Input Module Cat. No. 1794-IR8 125
Derating Curve
Specifications - 1794-IR8
Number of Inputs 8 Channels
Module Location Cat. No. 1794-TB3, -TB3S, -TB2, -TB3T, or -TB3TS
Terminal Base Unit
Signal Input Range 1 to 433 Ω
Sensors Supported Resistance:
100 Ω Pt µ = 0.00385 Euro (-200 to +870
o
C)
100 Ω Pt µ = 0.003916 U.S. (-200 to +630
o
C)
200 Ω Pt µ = 0.00385 Euro (-200 to +630
o
C)
500 Ω Pt µ = 0.00385 Euro (-200 to +630
o
C)
100 Ω Nickel µ = 0.00618 (-60 to +250
o
C)
120 Ω Nickel µ = 0.00672 (-60 to +250
o
C)
200 Ω Nickel µ = 0.00618 (-60 to +250
o
C)
500 Ω Nickel µ = 0.00618 (-60 to +250
o
C)
10 Ω Copper ∝ = 0.00427 (-200 to +260
o
C)
Resolution 16 bits across 435 Ω
Data Format Left justified 16-bit 2’s complement or
offset binary
Normal Mode
Noise Rejection
60db @ 60Hz for A/D filter cutoff @ 15Hz
Accuracy without
Calibration (low humidity)
Normal mode: 0.05% Full Scale (maximum)
Enhanced Mode: 0.01% Full Scale (typical)
Common Mode Rejection -120db @ 60Hz; -100db @ 50Hz with A/D filter
cutoff @ 10Hz
Common Mode Voltage 0V between channels (common return)
System Throughput
Normal mode:
Enhanced mode:
Programmable from 28ms/channel to
325ms/channel
325ms (1 channel scanned)
2.6s (8 channels scanned)
Programmable from 56ms/channel to
650ms/channel
650ms (1 channel scanned)
2.925s (8 channels scanned)
Settling Time to 100% of
Final Value
Available at system throughput rate
Open RTD Detection Out of range reading (upscale)
Open Wire
Detection Time
Available at system throughput rate
Overvoltage Capability
35V dc, 25V ac continuous @ 25
o
C
250V peak transient
Channel Bandwidth dc to 2.62Hz (-3db)
RFI Immunity Error of less than 1% of range at 10V/M
27 to 1000MHz
Input Offset Drift with
Temperature
1.5 mΩ/
o
C maximum
Specifications - 1794-IR8 (continued)
Gain Drift
with Temperature
Normal mode: 20 ppm/
o
C maximum
Enhanced mode: 10 ppm/
o
C maximum
RTD Excitation Current 718.39µA
Indicators 1 red/green status indicator
Flexbus Current 20mA
Power Dissipation 3W maximum @ 31.2V dc
Thermal Dissipation Maximum 10.2 BTU/hr @ 31.2V dc
Keyswitch Position 3
Cable Requirements 2-wire Belden 9501
3 -wire, less than 100ft (30.5m) with normal
humidity- Belden 9533
3 -wire, greater than 100ft (30.5m) or high
humidity (>55% for >8 hrs)- Belden 83503
General Specifications
External dc Power
Supply Voltage
Voltage Range
Supply Current
24V dc nominal
19.2 to 31.2V dc (includes 5% ac ripple)
19.2V dc for ambient temperatures < 55
o
C
24V dc for ambient temperatures < 55
o
C
31.2V dc for ambient temperatures < 40
o
C
See derating curve.
140mA @ 24V dc
Dimensions HxWxD 46mm x 94mm x 53mm (1.8in x 3.7in x 2.1in)
Environmental Conditions
Operational Temperature
Storage Temperature
Relative Humidity
Shock Operating
Non-operating
Vibration
0 to 55
o
C (32 to 131
o
F) See derating curve.
-40 to 85
o
C (-40 to 185
o
F)
5 to 95% noncondensing (operating)
5 to 80% noncondensing (non-operating)
30g peak acceleration, 11(±1)ms pulse width
50g peak acceleration, 11(±1)ms pulse width
Tested 5g @ 10-500Hz per IEC 68-2-6
Publications
Installation Instructions
User Manual
1794-5.22
1794-6.5.4
Agency Certification
Class I Division 2 certified
Groups A, B, C, D certified
Class I Zone 2 Group IIC certified
User Applied 24V dc Supply
19.2
31.2
24.0
0
o
C25
o
C40
o
C50
o
C55
o
C
Ambient Temperature
Safe operating area
The area within the curve represents the safe operating range for the module
under various conditions of user supplied 24V dc supply voltages and ambient
temperatures.
40156