How do I make a button that writes a setpoint value to the PLC?

[DataForge]

I'm building my first Omnivex SCADA project for a mixing station. Reading values works fine. Now I need two things on the operator page: a button that sets the mixer speed setpoint to a fixed value (for example 1200 rpm for a standard recipe), and a start button that writes 1 to a start bit in the PLC.
I see "EventHandlers", "Events", "Tag" and "Value" in the component settings, but I'm not sure how they fit together. The tag I selected for the setpoint doesn't seem to change in the PLC when I click the button. What do I need to configure?

[Technical Support]

Buttons send values through the component's Event Functions. The fields work together like this:

• EventHandlers: what triggers the action, for example a click.
• Events: the event command to run.
• Tag: the tag the component writes to.
• Value: the value that is sent.

Setpoint button
Add a Button component, set the click as the trigger, select the setpoint tag in Tag and enter 1200 in Value. For the start button, select the start bit tag and use 1 as the value.
Why the setpoint may not change
1. Function Type of the frame. A tag can only be written if its frame uses a writable function. Tags read from input registers or input status are read-only. The setpoint should be in a frame that reads holding registers (and the start bit in coils), as defined in your PLC's address map.
2. Data type and multiplier. If the PLC expects an integer and the tag is defined as a float, or a Multiplier Operation is set, the value arriving in the PLC can differ from what you expect.
3. The PLC program overwrites the value. Check whether the PLC logic writes the setpoint itself every cycle.
4. Communication. Confirm the channel is connected and the tag value updates on the page.
Recommendations
- For start bits, clarify with your PLC programmer whether the PLC resets the bit after starting, otherwise the bit stays at 1.
- If several setpoints belong together, a recipe may be a better fit than many single buttons.
- Use User Access on the page so only authorized users can send commands.
Documentation: https://greensoft.ai/documentation/o...ser-interface/