Rockwell Automation T743x-xx ICS Regent+Plus RTD Input Equipment - Manual (Page 24)

RTD Input Equipment (T7432)
2 4
Industrial Control Services
In this illustration, VALUE_A_NAME, VALUE_B_NAME,
and VALUE_C_NAME represent the three RTD inputs to be
mid-value selected. ERROR_A_NAME, ERROR_B_NAME
and ERROR_C_NAME are the error bits for the RTD inputs.
RESULT_NAME is the result of the mid-value instruction.
The field Limit is the integer value, in similar units to the
Value A, B and C variables, that a RTD input can deviate
from the mid-value result before signaling an error (via the
Error A, B or C bits). Once an error bit is set, it is latched.
RESET_NAME is the reset bit used to reset the latched error
bits.
RTD Signal Out of Range Conditions
The NOSIG contact in ladder logic function blocks can be used
to detect an out of range RTD input signal. The NOSIG
contact will be true when the RTD input signal is outside the
normal operation limits (see Table 1, Temperature Data
Ranges).
Maintenance
Calibration
The Mux contains an ultra-stable voltage reference circuit for
auto-calibration of all RTD channels. This circuit does not
require re-adjustment.
Safety Considerations
The RTD input modules are TÜV certified as non-interfering
and can be used for non-safety critical inputs in Risk Class 5
safety applications.
The RTD input equipment is TÜV certified as non-interfering
and when properly configured is also certified for Risk Class 5
safety critical inputs. Safety critical configurations include
redundant input modules and multiplexers and application
programmed midvalue selection methods.
Redundant RTDs can be used with redundant input modules,
termination panels and multiplexers to eliminate any single