User manual

PID Loop Operation
(DL450 Only)
Maintenance
and Troubleshooting
8--30
PID Loop Operation (DL450 only)
DL405 User Manual, 4th Edition, Rev. A
SP/PV Addresses
An SP/PV dialog will be made available to setup how the setpoint (SP) and the
process variable (PV) will be used in the loop. If this loop is the minor loop of a
cascaded pair, enter that control output address in the Remote SP from Cascaded
Loop Output area. It is sometimes desirable to limit the range of setpoint values
allowed to be entered. To activate this feature, check the box next to Enable Limiting.
This will activate the Upper and Lower fields for the values to be entered. Set the
limits around the SP value to prevent an operator from entering a setpoint value
outside of a safe range. The Square root box is only checked for certain PID loops,
such as a flow control loop. The Auto Transfer From I/O module will be grayed out
and not available for use by the DL450.
NOTE: Auto Transfer From I/O module is not available in the DL450 PLC at this
time, but will be available in the future.
If the Auto Transfer From I/O module is selected, an error message (shown below)
will appear.
NOTE: The SP/PV dialog can be left as it first appears for basic PID operations.