Analog signal from Acorn board

[tfhess]

report_38D2694D8E8B-0320180746_2020-10-17_08-24-23.zip

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I have been having trouble setting up my lathe spindle speeds. Firstly, I am running 4.20 software version and have a DC drive on the spindle controlled by a KBIC 225 with an SI-5 signal isolator board. So I did a test of the analog signal directly from the Acorn board with the Wizard set at 0 rpm low speed and 1000 rpm high speed, MDI call outs for spindle speed and with the following voltages:
Spindle call out speed; Voltage (DC)
S100; 2.52
S200; 5.02
S300; 7.52
S400; 10.03
S500 -1000; 10.03

A similar test with Wizard set from 0-2000 rpm resulted in voltages just half of above topping out at 10 v for an S800 call out.

This output seems wrong. Is the board kludged or something else going on? Any help would be appreciated.

[martyscncgarage]

Disconnect analog signals and rerun your test with DC meter probes connected directly to the ACORN board.
You will have to ultimately TUNE your KBIC-225 for the correct spindle speeds. Read the KBIC manual on that. You have a couple of pots to turn, MIN and MAX and you have to fiddle with them until you are satisfied.

Marty

[tfhess]

Thanks Marty. That is just what I did - checking the signal directly at the board, no KBIC connected. I expected to see a linear voltage climb from S100 to S1000 call out but got what I published above. Seems maybe I have to send the board in to Centroid.

[martyscncgarage]

Thanks Marty. That is just what I did - checking the signal directly at the board, no KBIC connected. I expected to see a linear voltage climb from S100 to S1000 call out but got what I published above. Seems maybe I have to send the board in to Centroid.

Did you change the values from your report?
Max spindle (high range): 2000.0
Min spindle (high range): 0.0

Did you do the spindle test during your bench test before connecting anything?
Any chance you miswired the analog signal output to the SI-5 board?
ALWAYS test the analog voltage during benchtest.

[tfhess]

Yes, changed the wizard between the max spindle speeds of 1000 and 2000. The connection between Acorn board and SI-5 was wired correctly - checked many times. I don't remember if I did an analog voltage test specifically, but think I did - my bench test was several years ago.

Is there any software ping or anything that could reset analog output? Or is this a hardware problem?

[martyscncgarage]

If it's been 3 years, your Acorn is out of warranty.
There is NO adjustment.
If you set High range min spindle speed to 0 and High range spindle speed Max to 1000, for every hundred RPM you should get a volt
100rpm= 1 volt
500rpm= 5 volts
1000rpm= 10 volts

[martyscncgarage]

You may qualify for the $199 swap out....
Are you absolutely sure your DC meter is good? Have another you can test with to be sure?

[tfhess]

Well, I was pretty sure I was headed for a swap out and $200 bucks gone.
My DC meter is fine, but would be worth checking with another meter.

Thanks for your replies.
T