Timer



  • I want to configure a timer functionality in Mervis like "press button connected to UniPi Digital In 1 -> switch on Relay 1, start a timer with an adjustable preset of x minutes to off -> switch off Relay 2 after timer runs out"
    I did discover a library box called "Lib.Hvac.V1_0.Timer". Unfortunately this box is not listed in the F1 Help of Mervis. The library box uses the local variables "TStart (udint)", "TimeFirstPart (udint)", "TImpMin (udint)", "TimePeriod (udint)" and "Status (sint)". Can someone explain the functionality of this library box, the variables and the usage please?

    Best regards,

    Matthias



  • I want to configure a timer functionality in Mervis like "press button connected to UniPi Digital In 1 -> switch on Relay 1, start a timer with an adjustable preset of x minutes to off -> switch off Relay 2 after timer runs out"
    I did discover a library box called "Lib.Hvac.V1_0.Timer". Unfortunately this box is not listed in the F1 Help of Mervis. The library box uses the local variables "TStart (udint)", "TimeFirstPart (udint)", "TImpMin (udint)", "TimePeriod (udint)" and "Status (sint)". Can someone explain the functionality of this library box, the variables and the usage please?

    Best regards,

    Matthias



  • Hello,

    the timer block is obsolete, please use the delay blocks instead. For your purpose, try BD13_SWITCHOFFDELAY which does exactly the thing you request.



  • Tomáš,

    the BD13 helped. Thank You.

    I have a further question. I want to control heating in this way:

    A heating element is controlled by Relay 1, temperature is measured by 1Wire sensor, now I want to set a temperature setpoint (e.g. 90 deg.C) -> "Start" -> heating until reaching the setpoint (measured temp => temp setpoint) -> hold temp for x minutes -> switch off heating.
    For holding the temperature I did test the B31_REVERSE_ON_OFF_CONTROL_SEQUENCE, but I don't no how to configure the whole application.

    Best regards,

    Matthias



  • Hi,

    I think that you could connect the switchoff delay block behind the B31 as you suggest or a simple gt/lt (greater than/less then - but this will not solve the hysteresis as the B31does).

    As it is written in the documentation, X is the actual temperature from a sensor, W is the setpoint when the output will become True, Xp is the hysteresis - eg if set to 5, the out will become True once the teperature goes below 90-5=95 thus the relay will not switch that frequently. Take a look at the graph on the help file….