Connecting Ni7344 to Compax C3

[tmoodley]

Hi

Im trying to connect an PCI version of the Ni7344 to a Compax C3 servo drive. I can commuunicate with the drive using it own software. When I set it up with the Ni-7344 the drive is ready (green led on drive flashes). i then use MAX to communicate with the drive. I set up the axis using MAX. I change the 3 dip switches to Active high on the UMI-7774. When I try to srvo tune the motor, no movement on the motor the drive gets energised and enabled (green led stays green). The filter setting gets maximised. There seems to be no analogue input signals being sent to the drive to command the drive to move.

Can anybody help me trouble shoot this problem?

Thivash 

[tmoodley]

More information about the drive

http://www.parker.com/euro_emd/EME/Literature_List/dokumentationen/C3I10T10%20eng.pdf

Im not sure about my UMI-774 pin assignments to the drive pins.

Im currently connecting my pins as shown in the attached files

[Jeffrey_P]

Good afternoon Tmoodley,

Let me start off by letting you know that there are many different things that could go wrong in a problem like this, and it may be difficult to troubleshoot via email or discussion forum. 

That being said, let's start with some of the more common issues that I have run into.  First, let's make sure that the drive is in the right mode.  Often times, the current/torque mode is not the default mode.  Our UMI's will only work well with drives that work in this mode.  When I say current/torque mode, I mean the following:  The drive receives an input voltage (-10 to 10 V) which is then linearly converted to a constant current (torque) which is supplied to the motor.  This may be a dip switch setting on the drive, or sometimes, a setting that has to be made in the accompanying software.

Secondly, ensure that the axis is enabled both on the drive and in the 1D Interactive status LEDs in MAX.  There might also be some LED's on the drive.  Anything that implies that the drive is disabled might lead us down a different path. 

Let's check these two things first and move on from there.  I thank you in advance for your patience!

Other possible common problems include the following:

a)  Incorect wiring

b)  Uninitialized motion controller

c)  Trying to use the wrong axis/axes

Respectfully,

[tmoodley]

Jeffery,  Thanx for offering assistance.

During the past two days I spent it with NI in South Africa to troubleshoot the problem.

We made significant inroads. problems we experienced was jumper settings on some of the drive pins and velocities too high. We can now communicate with the drive but still have many errors.

We are now stuck at the following problems.

1. Now the conrtoller is sending out a constant 0.01 volt analogue signal that moves the motor very slowly. The motor cannot be stopped. It travels at about 1rpm

2. The motor has a resolver and the drive converts these signals to a simulated encoder. These signals are now passed onto the controller via the umi to the controller. In MAX when I setup the motion  configuration if I select the feedback as encoder I see in the 1-D interactive window in the current trajectory data I see the counts and the velocity but they don't change. I a move is made the dive doesnot move the motor in the correct direction. If analogue feedback is selected the motion is in the correct direction. The drive counts/rev is 1024, which translates to a 5mm movement. When a motion is started the motor moves in the right direction more than target position and stops when the following error is increased. The current trajectory data is 0 and does not change.

3. If I press the halt button the motor reverses direction. Only the kill command can stop the motor.

4. I have connected forward (signal to feedback  pin (FP) 10, excittion to pin 13 & 22)and rear limit (FP 12 & excitation to FP 13 &22). Initially it worked fine I then changed the cables and checked the wires and now MAX sees this as fwd and home switches. I cant figure this one. Any words of wisdom.

This is all for now.

Regards

Thivash

[Jeffrey_P]

Tmoodley,

The constant voltage of 0.01 Volts implies to me that the Servo motor is not tuned properly.  I am attaching a link below:

http://zone.ni.com/devzone/conceptd.nsf/webmain/4B7775373E4AE64986256B6000691505

This link should walk you through the process of manual tuning your Servo Motor.  Go through this process, and then post back if you are seeing similar issues!

Respectfully,

[tmoodley]

Hi Jeffery,

I have manually tuned the servo motor seems to work. Im having all these problems because Im not getting any encoder feedback. The motor is fitted with resolver but the drive returns a digital +5V differential signal. This simulated encoder signal is fedback to the controller

In MAX I have set up the following:

Axis Config -- feedback = encoder

Encoder settings -- counts/rev = 1024 (same as in the drive)

     -- filter freq = 1.6 Mhz

    -- Polarities for A, B, N = Active high

   -- Index ref crit for A & B = Inactive

I move the linear actuator using the drive software and monitor the feedback with the 1-D interactive with MAX. When the actuator moves the the Current trajectory data starts just rapidly fluctuating by only one count. The feedback displayed in the drive software is correct.

This the same if I use the 1-D interactive window to move the linear actuator.

How do I set up MAX to be able to read the simulated encoder signal (digital RS422 5 volts differential signals)??

Thanx Thivash

[allen_h]

Hello Thivash,

It sounds like the problem lies with the encoder connection.  The UMI-7774 is expecting signals from a differential two-phase quadrature encoder.  The quadrature encoder outputs Phase A and Phase B TTL (0 to 5V) signals that are 90 degrees out of phase.

Is your encoder outputting this type of signal?  You can try connecting your encoder signal(s) to an oscilliscope and move your motor to check.

Allen H.

[tmoodley]

Hi Allen,

I have checked the same drive and linear actuator on the other three axes and they work fine. The setup for all four axes are exactly the same except for axes one which has a PWM setting. I have tried Axis-1 with enabled and disabled still no joy.

I'm wondering if the UMI is not faulty. The control signals from the controller to the drive seem to work fine. Is there a way I can verify if the UMI Axis-1 is faulty or not?

Regards

Thivash 

[allen_h]

Hello Thivash,

So if you connect this same drive/actuator/encoder to the other 3 axes, the current trajectory data will change correctly when you manually move our motor?

If so, set your Axis 1 settings in MAX to match one of the working axis's settings exactly.  Also, make sure your dip switches on the UMI match the working axis's dip switches.  Then, check if the current trajectory settings change correctly on Axis 1.

If using Axis 1 still does not work, then the problem probably lies with either the UMI or your PCI-7344.  If you have a second UMI-7774 or 7344, try swapping each one at a time to determine if the problem follows the original UMI or the original 7344.

Allen H.

[tmoodley]

Thanx Allen,

I have sent both UMi & PCI to Ni to check.

Regards

Thivash