The user can set maximum and minimum positions for the valve, as well as the maximum change allowed in one Scan Time. If the PID calculates a change in valve position that is less than the Minimum Change, the PID does nothing. This minimizes wear and tear on the valve. A complete description of the PID settings is given below.
Parameter | Description |
PID Name | Specifies which valve is to be controlled by the PID loop |
Mode | Either Normal (under PID control) or Manual |
Cur Pos | The current value of valve position (in % open or # turns open) |
Cur Out | The current output of the PID (ie where it thinks the valve should be) |
Max Pos | Maximum valve position allowed by the PID loop (set by the user) |
Min Pos | Minimum valve position allowed by the PID loop (set by the user) |
Max Chg | Maximum that the valve position can change in one move (set by user) |
Min Chg | Minimum that the valve position can change in one move (set by user) |
Man Mode | NO selects PID mode, YES selects PID mode |
Input | Selects which variable the PID loop will try to keep constant |
Cur Inp | Current value of the Input variable |
Set Val | Value (of the Input Variable) that the PID loop will try to maintain |
ST | Scan Time for the PID loop in seconds |
Gp | Proportional Gain setting |
Gi | Integral gain setting |
Gd | Differential gain setting |