Enabling Compumotor drive & strpper motor

[Airo]

Hi.


We have National Instrument�s PCI-7342 (motor controller embedded in a PC), Compumotor�s GT-L5 stepper motor drive, and Compumotor�s ES-22BS stepper motor. In the installation guide from Compumotor (product #: 88-017789-01 B), there are steps to set up the motor & drive with a third party (to Compumotor) controller. But, when I tried to enable the drive after configuring the drive I could not enable it. I think I followed the steps they explain exactly. But, somehow I can not see the motor shaft rotating (as a sign that the drive is enabled, we are supposed to see the motor shaft rotating). Do you have any idea what I should do?



Airo

[algames]

There are a couple of things you should consider while connecting the 7342 to the ES-22BS. First of all, make sure that the inhibit output signal of the 7342 has been configured for active high polarity in the UMI-7764 using the switches provided in the interface. Second, both the inhibit outout (which will go to the shutdown input on the ES-22BS) as well as the step and directio outputs on the 7342 are open collector or current sinking outputs. Since your drive's step, direction and shutdown signals are all optically isolated and thus require powering an optocoupler to work, then the current that they would require might be higher that what our outputs can generate. The proper way to connect optically isolated signals to the 7342 would be to use a +5v power supply
capable of sourcing the 6.5 mA minimum current required by your input lines (usually the same supply that you use to power the UMI) and connecting the +5v to the plus terminal of each of the signals (namely step+, direction+ and shutdown+). Then you will take each of the command signals form the 7342 and connect them to the respective minus inputs on the drive, so your connection diagram should be something like this:

1. UMI7764 ES-22BS


2. Step+ -> +5v


3. Step -> Step-


4. Direction+ -> +5v


5. Direction -> Direction-


6. Shutdown+ -> +5v


7. INHOUT -> Shutdown-

Since an open collector ouptut only has two states, either active low or floating, this scheme will allow your drive to see an active high signal when the output is low and an active low signal when the output ges into the floating state because the 7342 folats to +5v thorough an internal 3.
3K pullup resistor.

[Airo]

algames,


Thank you for your advise. It was relly helpfull. I have another question. You said:

The proper way to connect optically isolated signals to the 7342 would be to use a +5v power supply capable of sourcing the 6.5 mA minimum current required by your input lines and connecting the +5v to the plus terminal of each of the signals.......


Can I use the +5V & Digital Ground (they are called distributed power in the UMI manual) pins of UMI-7764 for each axis (we need just axis 1) to power the step+, direction+, and shutdown+ ?


Thank you.


Airo

[algames]

Yes, you should be able to connect it like that since the +5v terminals are supplied by the same supply that you use to power the UMI.

[Airo]

algames,


Thank you for your quick response. I was able to enable the drive fixing the RS-232 cable problem.

I have another question for you. Although I think I can wire like you told me, I have been wondered how I can send commands via cable put between the 50 pin connector of the GT-L5 drive and the motion I/O connector of the PCI-7342 controller (we have Motion Assistant software). I need to build a VI and let LabVIEW to do the job. Is it going to be a serial communication or something else? If you can tell me where I can find good VI expmples, I would really appreciate.


Thank you.


Airo

[algames]

Looking at the manual for the Gemini Drives, I found that on page 52 they have the specifications of the 50 pin connector pin out. In it you will find that pins 8-11 are differential step+ step- dir+ and dir- inputs. Pins 1 and 2 are the enable pins. The configuration from what I could gather would be the same to those done for the ES-22BS as I posted before. Again you will have to use the UMI-7764 interface to connect the pin out of our 68 pi9n connector to any of the two drives. The UMI is a screw terminal breakout box that exposes all of the Motion I/O signals on the NI-73xx controllers so on one side you would have the UMI and on the other side the 50 in connector that goes to the Compumotor drive.

[Airo]

algames,

After enabling the GT-L5 drive following the instruction from Compumotor, they said what I have to do is sending step and direction signal from our PCI-7342 controller for controlling the motor. (By the way, we have UMI-7764 between the PCI-7342 and GT-L5 drive.) So, I tried to configure the PCI-7342 controller using MAX. In MAX, there is a window, which is called �1-D Interactive� after going through My System >> Device and Interfaces >> PCI-7342(1) >> Interactive. In the �1-D Interactive� window, we can try to see if the motor moves or not. I tried the �1-D Interactive� thing with the wiring scheme you suggested and the one I tried (say original) before. I put the details of both wiring schemes below.

The o
ne you suggested:
UMI-7764 GT-L5
+5V--------------Step+
Step(CW)-----------Step-
+5V--------------Dir+
Dir(CCW)----------Dir-

The original wiring scheme
UMI-7764 GT-L5
Step(CW)-----------Step+
AOGND------------Step-
Dir(CCW )----------Dir+
AOGND-------------Dir-

In the �1-D Interactive� window, I put some number in �Target Position,� and hit the �Start� button (I did hit the Apply button too before hitting the �Start� button by the way). Still I did not see any motor movement. One of your software technicians told me that I should se some movement. Do you have any other suggestion?



Airo

[algames]

Before using the 1-D inetractive, you should make sure that the 7342 is configured to work as an open or closed loop stepper controller, otherwise you will not see the proper signals being sent out. You can do this very simply by selecting open loop stepper (for example) under the window that appears when you click on Default 7342 Settings in MAX. Once you have selected open loop stepper you can then press the Initialize button on top of the screen and that will set both of your axes for stepper configuration. To do a test move, in the 1-D interactive you can set your operation mode for veolcity and thyen start a move, this will start to generate a continuous step and direction signal that should move your motor conti
nuously until you press halt or kill. You can monitor if the controller is sending the signal properly by putting an oscilloscope across step and ground on the UMI's axis terminals where you want your motor to be configured to see if the controller is generating the pulse train it is supposed to. Keep in midn that the UMi terminals have labels that indicate which axis the signals belong to, you only have access to axis 1 and 2 for the 7342. The wiring scheme you used before was connecting a digital signal (step and direction) accross to an Analog Ground (AOGND) so there is a possibility that your UMI might be damaged too so trying it with a scope would be a good way to determine if there is a fault.