Hi folks

I'm new to Mach4 programming although I've a reasonable bit of experience with both Mach4 and programming individually :-)

I'm trying to configure Mach4 to control a VFD via MODBUS. I've the MODBUS bit up and working and can control the spindle via the "Diagnostic - Newfangled Solutions - MODBUS" screen but I'm having trouble wiring the relevant control signals to the MODBUS registers.

I can do this with a PMC script but a more elegant method would seem to be to use a signal script. However, went I try to set the register value I get an error "attempt to call a nil value (field 'RegSetValue')" I've added some debugging messages and I can see that the 'hreg' variable is getting a value.

The code below has been added to my screen load script in the 'SigLib' section. I'm just using test registers for debugging.
[mc.OSIG_SPINDLEFWD] = function (state)
    if (state == 1) then
local hreg = mc.mcRegGetHandle(inst, "iRegs0/test/spindleCtrl")
mc.RegSetValue(hreg, 1)
    else
mc.mcCntlSetLastError(inst, "INFO: OSIG_SPINDLEFWD != 1")
local hreg = mc.mcRegGetHandle(inst, "iRegs0/test/spindleCtrl")
mc.mcCntlSetLastError(inst, "INFO: hreg value was " .. tostring(hreg))
mc.RegSetValue(hreg, 0)
    end

end,
I get the error when I click on 'Enable' in Mach4, I'd assume part of the enable process is to set the motor off so that makes sense.

Any help would be greatly appreciated.

Tommy

Never mind folks, the classic case of 'read the manual one more time after posting a forum message'

The command is, of course, 'mc.mcRegSetValue(hreg, 0)' rather than 'mc.RegSetValue(hreg, 0)'

Doh!