Controlling a Ratio (PID)
u can maintain two values in a ratio by using these parameters:
- Uncontrolled value
- Controlled value (the resultant setpoint to be used by the PID instruction)
- Ratio between these two values
Relay Ladder
![FTStudio-PID-LD-EX2-V1](/content/dam/dita/en/factorytalk-design-studio/current/online-help/topics/instructions/common-content/graphics/ftstudio-pid-ld-ex2-v1.png/_jcr_content/renditions/original)
TIP:
Tip: To avoid locking up the PID with invalid internal floating point values, ensure the PV is not INF or NAN before invoking the instruction such as:
XIC (PC_timer.DN)
MOV(Local:0:1.Ch0Data, Local:0:1.Ch0Data)
XIO(S:V)
PID(...)
For this multiplication | Enter this value |
---|---|
Destination | Controlled value |
Source A | Uncontrolled value |
Source B | Ratio |
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