Specifications
Publication 1794-SG002D-EN-P - May 2012
Select FLEX I/O Modules 45
Thermocouple/RTD Input Module
Specification 1794-IRT8 and 1794-IRT8XT
Input resolution 14 bits
Supported RTD types Resistance:
100 Ω Pt μ = 0.00385 Euro (-200…870 °C)
100 Ω Pt μ = 0.003916 U.S. (-200…630 °C)
200 Ω Pt μ = 0.00385 Euro (-200…400 °C)
200 Ω Pt μ = 0.003916 U.S. (-200…400 °C)
100 Ω Nickel μ = 0.00618 (-60…250 °C)
120 Ω Nickel μ = 0.00672 (-60…320 °C)
200 Ω Nickel μ = 0.00618 (-60…200 °C)
10 Ω Copper μ = 0.00427 (-200…260 °C)
Supported Thermocouple types Type B: 300…1800 °C (572…3272 °F)
Type E: -270…1000 °C (-454…1832 °F)
Type J: -210…1200 °C (-346…2192 °F)
Type K: -270…1372°C (-454…2502 °F)
Type N: -270…1300°C (-454…2372 °F)
Type R: -50…1768°C (-58…3214 °F)
Type S: -50…1768°C (-58…3214 °F)
Type T: -270…400°C (-454…752 °F)
Type TXK/XK (L): -200…800°C (-328…1472 °F)
Accuracy 0.05% of full range in mV mode with filtering selected
Hardware only = 0.10% of full rang in mV mode
Common mode rejection ratio -80 dB @ 5V peak-to-peak 50…60 Hz
Common mode input range Series A – ±4V
Series B – ±15V
System throughput 7.4 ms – mV
8.0 ms – Ω – 2-wire
10.0 ms – Ω – 3-wire
10.4 ms – Ω – 4-wire
8.0 ms – Ω – 2-wire RTD (°F)
10.4 ms – Ω – 4-wire RDT (°F)
8.8 ms – Ω – 2-wire RDT (°C), (°K)
10.8 ms – Ω – 4-wire RDT (°C), (°K)
9.8 ms – Ω – 3-wire RDT (°F)
10.0 ms – Ω – 3-wire RDT (°C), (°K)
8.0 ms – Thermocouples (°F)
8.8 ms – Thermocouples (°C), (°K)
(1)
Open circuit detection type Series A: RTD and TC modes – open input – module defaults to
max value
Series B: RTD mode – open input – module defaults to
max value
Series B: TC mode – open input – module defaults to min value
Excitation current 630 μA
Overvoltage capability Series A: 7V DC continuous @ 25 °C
Series B: 15V DC continuous @ 25 °C
Open input detection time 0…3.8 s for Series A, revision D or earlier
Immediate detection (max 2 scans) for Series A, revision E or
later
Immediate detection (max 2 scans) for Series B
Cold junction compensation range 0…70 °C for firmware Series A, revision D or earlier
-20…100 °C for firmware Series A, revision E or later
-20…100 °C for firmware Series B
Cold junction compensation A-B Cold Junction Compensation Kit, 1794-CJC
(2)