4-Relay Unit question

  • I just bought some 4-Relay Units (i2C) and I found that there are two operating modes; synchronous and asynchronous. The documentation does not describe the difference between these modes except to say, don't use asynchronous!

    from documentation - UIFlow functions
    "Set LED and relay mode
    LED and relay ON/OFF are synchronized.
    LED and relay ON/OFF are asynchronous."

    1. Can anybody shed light on what they are referring to? Does this mean that in asynchronous mode you can select the LED and Relay separately?? Or does it refer to the settings of the individual relay values?

    from documentation - RELAY control Reg 0x11
    "Note:The relay can only be controlled in synchronous mode, if the relay is controlled in asynchronous mode, it will not work."

    1. If we are not supposed to use the asynchronous mode the why the heck do they let you select it???

    Thanks in advance!

  • Hello @robjasey

    the description is misleading, I can use both modes and they do as I'd expect. Synchronous mode: relay and LED go together. Asynchronous mode: relay and LED can be controlled separately.

    Here is what I found using UIFlow 1.10.6 and the 4-Relay unit:
    Synchronous mode:

    • turn on relay works (LED turns on too)
    • turn off relay works (LED turns off too)
    • turn on LED does not work
    • turn off LED does not work

    Asynchronous mode:

    • turn on relay works (LED does not turn on)
    • turn off relay works (LED does not turn off)
    • turn on LED works
    • turn off LED works

    I suggest you just give it a try.


  • @felmue Thanks for you fast reply Felix!
    I will.