Rockwell Automation 1769-IR6 Compact I/O 1769-IR6 RTD/Resistance Input Module - Manual (Page 49)

Rockwell Automation Publication 1769-UM005B-EN-P - March 2012 49
Module Data, Status, and Channel Configuration Chapter 4
Open-Circuit Flag Bits (OC0…OC5)
Bits OC0…OC5 of word 6 contain open-circuit error information for
channels 0…5, respectively. For an RTD input, the bits indicate either an open-
circuit or short-circuit condition when set (1). For a resistance input, the bits
indicate an open-circuit when set (1).
Over-Range Flag Bits (O0…O5)
Over-range bits for channels 0…5 are contained in word 7, even-numbered
bits. They apply to all input types. When set (1), the over-range flag bit
indicates an RTD temperature that is greater than the maximum allowed
temperature or a resistance input that is greater than the maximum allowed
resistance for the module. The module automatically resets (0) the bit when the
data value is again within the normal operating range.
Under-Range Flag Bits (U0…U5)
Under-range bits for channels 0…5 are contained in word 7, odd-numbered
bits. They apply only to RTD input types. When set (1), the under-range flag
bit indicates an RTD temperature that is less than the minimum allowed
temperature. The module automatically resets (0) the bit when the data value is
again within the normal operating range.
TIP Short-circuit detection for direct resistance inputs is not
indicated because 0 is a valid number.
TIP There is no under-range error for a direct resistance input,
because 0 is a valid number.