7i76 spindle setup

Im having trouble setting up the 7i76 for +/-10v control of the spindle for easy CW and CCW control

the spindle is a DC motor running off is a Sprint 340XRi which i have tested with a Pot and works fine for CW and CCW operation.

The 340Xri generates the -10v but seems to be ok. When I connect the -10 and +10v to the 7i76 the Spin- drops to -7.2 but spin+ is 10v. When I run the spindle from MDI it starts at -7.2 and when the speed is incremented on the + button it jumps to 10v and drops down to 0 as the + button is pressed.

I haven't connected the 340xri to the controller yet as I wanted to get the signals working correctly first. I checked +/- control in PCconfig but it doesn't seem to work. Could someone have a look and see if I have a setting wrong? Thanks in advance

If you connect +10 and -10V to a 7I76 analog interface you may damage it
(it expects 15V maximum between SPIN+ and SPIN-)

If you need bipolar operation, you can run the analog interface from +- 7.5V but you would probably
need to use the scale component to add a 1/2 scale offset to the spindle speed command in hal

Ah! that could be a problem then, fingers crossed I haven't damaged the board!

I don't need bipolar but it just seemed an easier way to set up the direction control of the spindle and I thought it might transition better for indexing when using Orient.

I can wire it up for the push buttons if required. Can I connect the Spindle enable direct to the 340XRI pin 9 , if I connected feild GND to the com line, or would it be better to relay it to keep the earths separate?

Me end goal is to use the spindle for indexing (with a brake) so what would be the best way to set it up? Cheers

The 7I76's spindle enable and direction outputs are floating switches
(Opto-isolator outputs) and have no common pins with field or logic power.

If you have a active low enable (pull down to enable) for example you connect:

7I76 ENA+ --> Drive enable input
7I76 ENA- --> Drive enable common

If you had a active high +24V enable, you would wire
+24V --> 7I76 ENA+
7I76 ENA- --> Drive enable input
(and 24V common to the drives input common)

Thanks that makes more sense now,
As long as I haven't damaged the board then I have a few options to try. First job is to get it working and then I can tweek later if its not quite right.

Thanks again

Well the good news is I didn't damage the 7i76 with the +/-10v.

Problem is I cant seem to find the right wiring set up to make it work with only 0-10v. the controller seems to need +/-10v and the different diagrams basically swap the +10 to the -10 feed which means that spin+ is negative and wont work as it below 0v

will it work if if I did a switch over relay to make spin- -10 and spin + 0v?

I have set the spin out to 7.5v and adjusted the max output on the 340XRI but it wont get any were near 1000rpm so not really an option to scale a +/-7.5v supply.

The only 2 options I can see is to use an external controller that can accept step direction to generate +/-10v or try a +10-5v steup as I dont need full RPM in reverse. (its only for indexing)

Have I missed an easier option?

Is there a real manual for the drive that explains the speed control input?
The partial manual I found seems to indicate some kind of polarity swapping inputs (pushbutton+ pushbitton -)

Sorry I thought Id attached the manuals.

Yes the options all seem to swap the +/- by either external relays or the internal logic.

As far as I can tell you should be able to get bidirectional operation by driving PB8 with the 7I76s DIR output

Drive 7I76 TB4
1 --> 3 SPIN+
5 --> 1,5,7 SPIN-, ENA-,DIR-
6 --> 2 SPINOUT
8 --> 8 DIR+
9 --> 6 ENA+

That might work, I would have to connect pin 3 and 4 together as the inverted signal feed to pin 6 is output on pin 4.

I have emailed Sprint to see if that would be OK. I think the push buttons are latching so both are needed on a change over.

I have seen the similar thread RE +/-10v for indexing and I noticed that you said the analogue spindle output isn't fast enough for indexing. Would i be better to use the step gen output and then a converter for PWM with a +/- 10v outputs like a dc servo drive?