What is a limit comparator, and how is it configured?
The JUMO DICON 400/500 or 401/501 provides the option of programming up to 8 such limit comparators.
In order to make the best use of a limit comparator, it must be programmed for the required switching response.
The switching response is defined by the limit comparator functions (lk 1 - lk 8).
lk 1 - lk 6 are functions based on the setpoint, and lk 7 - lk 8 are based on fixed limits.
For lk 1 - lk 6, the AL (alarm level) is the difference between the setpoint W1 and the switch-on or switch-off point.
For lk 7 - lk 8 the AL is an absolute limit value at which the contact will switch on or off.
Function lk 8 > limit value 70 °C, the assigned output remains switched on unless the process value rises above 70 °C, whereupon it is switched off.
If the process value falls below 70 °C, the output is switched on again.
The return switch-on point can also be controlled by a switching differential.