Rockwell Automation 1771-TCM TEMPERATURE CONTROL - Manual (Page 37)

5–2 Configuring the Loops
Publication 1771Ć6.4.5 - January 1997
6. Repeat from step 2 until you have made all desired changes to the
loop list.
On the Configuration screen, you are given several configuration
selections to establish. However, your selections do not control the
PLC data table values in real time. These selections do not take
effect until you download the selections to the PLC data-table
interface area.
If a loop input circuit becomes open (a wire breaks or vibrates loose)
the loop can not measure the temperature. In automatic mode, the
lack of temperature feedback would make it impossible to control the
temperature. To guard against such a lack of temperature control,
the module provides open-circuit detection.
You select a mode to which the loop is to switch when an open input
circuit is detected in automatic mode. The selections are:
•
disable the PID loop by forcing the manipulated variable (M)
value to zero
•
set the output to the open-circuit forced M value
•
set the loop to the manual mode (force M to manual output value)
Configuration Selections
OpenĆCircuit Detection