[LOCK_LM] Locking limitation

Function block LOCK_LM limits a control value based on a locking value [LockVal].

LOCK_LM limits a control value based on the locking value [LockVal] (0% to 100%). LOCK_LM calculates the max. permissible control value based on the locking value [LockVal] and the present control value [Val]. Inputs [ValMin] and [ValMax] specify the invalid range from [Val] and [LmValMax].

Functioning

A locking signal of 0% means that there is no current limitation. If energy limiting function is inactive, output [LmValMax] is set to [ValMax]. If [LockVal] increases, [LmValMax] is lowered continuously to a min. of [ValMin]. If [LockVal] decreases, [LmValMax] is increased to the max. of [ValMax].

For an immediate control value response, the actual control value must be indicated at input [Val]. When [LockVal] changes direction, [LmValMax] is set to [Val].

Pins

Input

Description

Data type

Default value
Value range

LockVal

Locking value

Real

0.0

0.0…100.0 [%]

Val

Value

Real

0.0

ValMax

Maximum value

Real

100.0

ValMin

Minimum value

Real

0.0

 

Output

Description

Data type

Default value
Value range

LmValMax

Maximum value limit

Real

100.0

Application

LOCK_LM can be used to limit heat consumption of a device, when the heat generator must reduce load. In this case, LOCK_LM can limit the output of the actuating device or directly with the setpoint used to control.

Troubleshooting

The values at input [LockVal] are limited to a range of 0% - 100%.