GPIO4 fails to start my spindle.

[Exhibitology]

I am struggling to connect a TB Woods WFC inverter to a
Centroid MPU11 / GPIO4. All other systems are functioning.
This is my last huddle to making chips.

I've installed a half dozen Woods inverters over the last
decade on various CNC spindles. Most recently a TB Woods
X2C to a Centroid All-in-One system.

This time I'm stumped.

The inverter accepts a 0-10VDC signal for analog input.

The start command is a +24VDC common provided by
the inverter connected to its forward terminal.

When I make this connection manually the spindle accellerates
to it's minimum speed. When I break this connection, it decellerates.

However, connected to the analog and common outputs from
the GPIO4 and with the forward command and +24VDC wired
through outputs 7 and 8, I get nothing.

Not with the pendant, not with keyboard commands, and
not with a test file.

I've checked the MPU11 PLC file loaded and confirmed
that "out7" provides the start/stop spindle command.

I've checked the out7 terminals while a file is running and I'm not
getting continuity. The GPIO4 is not sending a signal to the out7 relay.

There must be something simple and stupid I've overlooked.

Is there anything anyone can think of?

Thanks

Rich

[cncsnw]

Is one (or more) of your limit switch inputs open?

In general, any tripped limit switch will stop the spindle and prevent it from starting.

Depending on your PLC program, it may respect the limit switch numbers entered on the Machine Configuration screen (so that only those inputs listed as limits on that screen are checked), or it may require that all of INP1 through INP6 be closed, regardless of whether they are all being used as limits or not.