Rockwell Automation 1794-IRT8XT FLEX I/O Thermocouple/RTD /Millivolt Input Module User Manual - Manual (Page 41)

Publication 1794-6.5.12 - September 2011
Read and Write Configuration Maps for the FLEX I/O Module 29
Fault Mode
You can enable or disable the fault detection. When enabled in thermocouple
mode, each channel is monitored for an open circuit. If an open is detected,
the overrange and fault bits are set for that channel, and the channel data is set
to the maximum value (Series A), or minimum value (Series B) for the chosen
mode of operation.
When enabled in RTD mode, each channel is monitored for an open circuit
(RTD and wires) and short circuits (RTD). If an open is detected, the
overrange and fault bits are set for that channel, and the channel data is set to
the maximum value for the chosen mode of operation. If a short is detected,
the underrange bits is set for that channel, except when in
Ω mode. The
channel data is set to the minimum value for the chosen mode of operation.
RTD Offset
You can select from four fixed resistive values used by the module when inputs
are configured for 2-wire with user selected RTD offset. The RTD offset is
used to nullify the effects of the resistance of long lead wires. Each value
represents the total resistance of both leads of a 2-wire RTD. For example, if
you choose 5
Ω , the module compensates for a total of 5 Ω of lead resistance.
You can perform a calibration operation that measures the actual total lead
resistance with RTD replaced with a short circuit. The value stored from this
operation is used when the option Use Channel Loop Compensation Value is
selected. This is also the default setting and is initially set to 0 at the factory.
Each channel has its own pair of RTD offset bits and a Channel Loop
Compensation value.
Sensor Types Individual input channels are configurable to operate with the following sensor
types:
RTD Type Thermocouple Type
Sensor type for channels 0…3 Sensor type for channels 0…3
Sensor type for channels 4…7 Sensor type for channels 4…7
Resistance (default) mV (default)
100 Ω Pt α = 0.00385 Euro (-200 … +870 °C) (-328…1598 °F) B 300 … 1800 °C (572 … 3272 °F)
200 Ω Pt α = 0.00385 Euro (-200 … +400 °C) (-328…752 °F) E -270 … 1000 °C (-454 … 1832 °F)
100 Ω Pt α = 0.003916 U.S. (-200 … +630 °C) (-328…1166 °F) J -210 … 1200 °C (-346 … 2192 °F)
200 Ω Pt α = 0.003916 U.S. (-200 … +400 °C) (-328…752 °F) K -270 … 1372 °C (-454 … 2502 °F)
100 Ω Nickel α = 0.00618 (-60 … +250 °C) (-76…482 °F) TXK/XK(L) -200 … 800 °C (-328 … 1472 °F)
200 Ω Nickel α = 0.00618 (-60 … +200 °C) (-76…392 °F) N -270 … 1300 °C (-450 … 2372 °F)