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Are Dirve Inerface signals Sink or Source?

Posted: Wed Sep 03, 2025 6:01 pm
by GlennE
I'm using the Flying Lead cable #13133 to connect to model MR-J3-A Mitsubishi Servo drives. The Inputs are currently wired for Sinking control.
I need to verify that the OAK's ENABLE (Pin 21, Brown wire) is functioning. What is the Output bit in the parameter display for Centroid's OAK CNC?

If the connection is NOT sinking, I will need to add a relay to invert the control. I am reading the Servomotor encoders perfectly.

I might hard-wire the enables ON, but I'd rather not. When I complete this retrofit, I will release the schematic and parameters for the servo drives and the Yaskawa spindle drive.

Re: Are Drive Interface signals Sink or Source?

Posted: Wed Sep 03, 2025 9:22 pm
by cncsnw
We have to be careful to define this, since different people have different ideas about what "sinking" and "sourcing" mean.

I use those terms to describe one side of a connection, and whether that one side provides a connection to positive (sources current) or a connection to negative (sinks current) when the signal is active.

In that sense, the Oak ENABLE signal is a sinking output: it provides a closure to 0VDC when the Oak wants to enable the servo drive. Therefore, it would work with a sourcing servo drive enable signal: one with an opto-coupler, the other side of which is connected to +24V.

When Oak enables the drive, current flows from +24V, through the drive's input opto-coupler, through the Oak's output opto-coupler or transistor, to 0V.

Servo drive enables on Oak and other Centroid DriveBus devices are not PLC outputs, and are therefore not visible on the Alt-i display.

If you add PLC logic to echo SV_PC_POWER_AXIS_n to some PLC memory bits (similar to what many mill PLC programs already do with SV_PC_POWER_AXIS_3 and a ZBrakeRelease output), then that would give you something you could watch on the Alt-i display.

Re: Are Dirve Inerface signals Sink or Source?

Posted: Thu Sep 04, 2025 6:14 am
by GlennE
Thank you. My servo-amps ARE wired as SOURCE. They require SINKING control (connect to 0vdc) so we're good. I'll use a 'scope and verify I'm getting the STEP pulses. I may need to change the drive parameters to match whatever the OAK outputs for control pulses.