6. Function blocks
6.1 Manufacturer function blocks
Level control
The contents of a liquid tank must not fall below or exceed a specific liquid level.
The ACTUAL value (level) is higher than the SETPOINT, meaning that liquid needs to be
drained. Function block output Q1 switches the drain valve on.
The ACTUAL value (level) is lower than the SETPOINT, meaning that liquid needs to be
replenished. Function block output Q2 switches the supply valve on.
Hysteresis values H1 and H2 define how long liquid needs to be drained or replenished.
This also means that they define the volume before draining and after replenishing.
See also
→ Section "TC - Three step controller", page 297
→ Section "FT - PT1-Signal smoothing filter ", page 279
→ Section "VC - Value limitation ", page 302
→ Section "BC - Block compare", page 306
→ Section "BV - Boolean operation", page 353
→ Section "PO - Pulse output", page 284
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