Set up using AMC AB15A100 drives, brushed DC motor Prototrak Plus with Encoders

Many, many thanks, tommylight & PCW!! There is no tacho. I do not believe the velocity loop is closed. I will review velocity loop literature, over the weekend. Many thanks!
After re-reading the 7i77 manual "OPERATION" section: The last 2 sentences talk about shielded twisted pair of wires, with the shield connected at the 7i77 GND end only. With this addition: The drives common or GND signal (position 2 on the AMC drive) should be connected to the 7i77 power GND with separate wire; this is to the GND for the whole electrical panel? There is a separate GND screw on the base of each drive that I use to go to GND also.

In the next paragraph in the 7i77 manual; Servo Enable Outputs "states enable outputs are polarized and can be damaged".

It is for this reason that I am asking for a 2nd opinion in reference to how correct the diagram that I am offering is.

I belief that I have read the manual correctly, the diagram I have provided needs a drive common or signal GND, (position 2 on the AMC drive) to go to the 7i77 power GND with separate wire?

I am assuming (referencing to the 7i77 manual ) that "AIN +" & "AIN -" are "+REF IN" (4 position on P1) & "-REF IN" (5 position on P1) on the AMC drive.

Many thanks for all the help: I pray this diagram is close to correct.

Edit: I have reread a prior post that test (this was specifically in reference to 12A8 drive, not AB15A100) with the SW1-1 to -3 = OFF & SW1-4 to -6 = ON; starting with POT4 at mid point; turning POT 4 to change direction of motor. This is to test if motor direction can be changed, w/o Linuxcnc power up. All the green LED are on the drives, the drives do not runaway, but the motor does not move or change direction (the change in direction is what is required), but will spin by hand. This is the correct way to test the diagram?

Many thanks.

I have been searching for electoral help for a while & hope and pray that this gentleman has that knowledge. My I ask the forum members to give him a warm welcome, a servo electrician/technician who usually works with PLC controlled servos in an industrial environment. It has taken some time for me to find someone who believes he can help with my application, and will be following this posts. After some face to face reviewing the 7i77 manual, motor spec. sheet, AMC data sheet, in addition to the diagram at the top of this post we are un-shore where or how to start.

I have a diagram at this address in a prior post, (this is the only method that worked to copy link) the very last page, at the bottom after PCW offered helped with AMC a12a100 using tachometer feedback.

forum.linuxcnc.org/12-milling/41356-a-m-...totrak-plus?start=90

Can we use this diagram as a starting point?? This is for tachometer feedback; I believe I need to use encoder velocity mode.

Many, many thanks, all suggestions are warmly welcomed.
 

I don't think that you will be using Hall sensor with a DC drive (first pic in this thread) but I think that the encoder connection is correct (as the drive seems to use either encoder velocity or tachometer)

You can probably run the drive open-loop but running with a velocity loop in the drive is likely to be easier to tune.

andypugh, Many thanks for your help!! The encoders are working, they count & are the correct direction. The motor, up to this point, I can't use POT 4 (I believe is the proper POT, with the proper switches at (SW1) in place) to change direction of motor w/o Linuxcnc running. It is the motor, to the 7i77 card, to the driver, wiring diagram I think is the unknown part. It is early now, I have emailed my electrician.
Many thanks for the help!

I have read this at post #9 at this link: www.cnczone.com/forums/servo-motors-driv...a20-torque-mode.html

This describes that AMC drivers require a way to inhibit the drive. Does this apply to my application?

Many thanks, for all help is warmly welcomed.



"Re: Setting up AMC BE25A20 in torque mode?

I am currently working on a retrofit using the Mesa 7i92, 7i77, and AMC 30A8 drives in torque mode which should be very similar to your setup. I don't know if you have seen them, but AMC has multiple manuals on their site that provide details on how to setup the drives in torque mode, adjust offsets, and such. Go to their website and search for your model:

www.a-m-c.com/products/?page=product&id=25A20

This will give you the datasheet for your specific model. On the above page, if you click on the reserved and discontinued items link, there will be a link to the classic analog drives HW manual which has a bunch of good information on setting up the drives. A direct link is here:

www.a-m-c.com/wp-content/upl...alog_Panel.pdf

PCW_MESA is correct in that the inhibit line left open enables the drive by default (it has an internal pull-up to +5VDC). I wanted the drive to be disabled by default and and didn't want to modify the drive's circuit board so I am using a normally closed solid state relay to pull the inhibit line to ground at power up or any other time when either the E-Stop is triggered or the drive enable switch isn't turned on. I also use another NC SSR for the fault line feedback to the 7i77 since I'm using 24VDC for field IO and the AMC drive uses a 5VDC TTL output. I can provide a hand drawn schematic for my interface board if you are interested. It uses 6 x CPC1333G ICs (4 pin DIP NC SPST SSR) and 6 resistors for current limiting."

Many thanks andypugh for your help! This is you offering the diagram describing "DC servos with tachometers. A +/- 10V analogue control signal into the drive" (12 Dec 2016 09:55 #83938 the link:
forum.linuxcnc.org/12-milling/31949-deck...4ma-retrofit?start=0 )
Could I start with this diagram and where the tachometers attach, replace with encoder input??
The diagram is at this link, I will try to attach pic: forum.linuxcnc.org/media/kunena/attachments/723/Deckel_p115.pdf