Analog spindle signal

[Nigelo]

I used LAPP Kabel, Stuttgart's Olflex CY multi-core screened cable on my Router as this was used by Wabeco who manufacture my precision Mill in Germany.

This is available from RS Online (in Germany https://de.rs-online.com/web/ )
RS stock code for my 7 core (black conductors individually numbered 1 through 7) is 141491 for 50 metre reel. Other lengths will surely be available

[ShawnM]

We were talking about the signal cable that goes from the Acorn to the VFD that carries the analog signal, that needs to be a shielded, twisted pair of wires say around 22-24 gauge. Add a single .1 mfd cap at the acorn board across the wires and call it done.

And yes, the wire that leaves the VFD and goes to the spindle ALSO needs to be a shielded wire but of course much heavier gauge. That depends on your rated HP of the spindle.

[tfhess]

Yes, l use a shielded, twisted pair of wires for the analog signal.

With regard to original post, I have now grounded all cable shields and installed caps on the analog signal. However, I still get the same problem when testing the signal - 0.93V when it should be 1.67V.
For a lark, I ran the spindle bench test routine similar to a real bench test, but with the acorn installed in the enclosure. No connections to the acorn board except power. And the test ran successfully, giving me the correct output voltages. (The drive controllers and VFD were powered up, just not connected to board)
Hmmm. This indicates to me that something on the plug ins to the acorn board may be causing the problem. I checked a few of them with all connections back to board e.g. the drive ok connection (input 5), but that was not it.
Perhaps it is the connections to the servo drives causing problems? Not sure how to ascertain that.

[rk9268vc]

With regard to original post, I have now grounded all cable shields and installed caps on the analog signal. However, I still get the same problem when testing the signal - 0.93V when it should be 1.67V.

unplug from VFD and measure at the end of the cable. While plugged in, VFD could be pulling it down

[tfhess]

On one test, I measured directly at the board (no cable) on the other the cable was not connected to VFD, but run through capacitor. Both had the same 0.93V reading.

[rk9268vc]

On one test, I measured directly at the board (no cable) on the other the cable was not connected to VFD, but run through capacitor. Both had the same 0.93V reading.

put your spindle in manual mode and set it to full speed and see if you get 10V
If you only get 5, go into the wizard and see if you have it set to 5V max