5.17. LCS¶
Purpose
The Level Control Switch (LCS) can be used to switch on at one level and to switch off at another level. In fact it is a combination of two COND components. For example:
Pump sump (On-value > Off-value): When the level in the collection reservoir exceeds a certain value the pump is switched on. When the level drops below a certain value the pump is switched off.
Pressure system (Off-value > On-value): When the pressure in the system falls below a certain value the pump is switched on, to re-pressurise the system. When the pressure exceeds a certain value the pump is switched off.
Procedure
The sense of the operation depends on which of the two values are greater.
On-value > Off-value:
Output will become TRUE if the input signal exceeds the On-value.
Output will become FALSE if the input signal drops below the Off-value.
On-value < Off-value
Output will become TRUE if the input signal drops below the On-value.
Output will become FALSE if the input signal exceeds the Off-value.
Parameters
Parameter |
input |
unit |
range |
default |
remarks |
|---|---|---|---|---|---|
On value |
real |
||||
Off value |
real |
||||
Reset time (on) |
real |
[s] |
|||
Reset time (off) |
real |
[s] |
|||
Initial status |
ON/ OFF |
Remarks
Both On/Off-conditions must hold for periods longer than their corresponding ‘reset time’ before the output will switch to TRUE or FALSE. If the conditions do not hold for periods longer than their ‘reset time’ then the output will not switch.
Examples
Pump sump: On-level > Off-level.
If the level in the collection reservoir has risen to a certain level, it is emptied by the pump to a certain lower level
Pressure system: Off-Level > On-level
If the pressure in the system falls below a certain level the pump starts to re-pressure the system. After reaching a certain high level the pump stops.
