Using the ENABLE output of the UMI-7774

[GregH]

I have a motion control system using the NI-7354 4-Axis controller, and the UMI-7774 interface. I am trying to use the ENABLE line for each axis to manually enable and reset the drive for each axis. I am using NI-Motion calls in Visual Basic to do so. I have setup the outputs using the following function call for each axis:

miStatus = flex_config_inhibit_output(b7354MotionCtrlBoardID, AxisNum, DISABLED, NON_INVERTING, NIMC_OPEN_COLLECTOR)

and I toggle the ENABLE lines using the following command:

miStatus = flex_set_inhibit_output_momo(b7354MotionCtrlBoardID, iMustOnMask, iMustOffMask)

I can successfully toggle the DISABLED LED on the UMI-7774 for each channel, but I am unable to see an output difference at pin 6 to control the drive enable line.

Viso has 24Volts connected

Ciso has 24V return connected

The ENABLED dip switches are set to ACTIVE HIGH for each axis

I've tried using Inverting and non-inverting polarity and setting the dip switches to ACTIVE LOW and I am unable to see any difference at pin 6 when I toggle the ENABLED line on and off.

any suggestions?

[Angela M]

Hello GregH,

When trying to measure the output on the Enable line there are a few thing to consider.  For reference refer to page 3-6 and 3-12 in the NI UMI-7774 User Manual.  This User Manual is installed with the motion driver under National Instruments>>NI-Motion>>Documentation>>Accessories on your computer.  If you are successfully toggling your enable LED, then you will see a voltage difference when measuring between pin 6 of the control connector and CISO.

I hope this information helps.  If you have any more questions about this, let me know.

Regards,

Angela Morris

National Instruments

[GregH]

I am familiar with the UMI-7774 manual. We have been using it all along to try to troubleshoot this issue.

We are measuring voltage between pin 6 and Ciso, but the problem remains, that even thought I can successfully toggle the LEDs for each axis, I am not seeing any voltage difference between pin 6 and Ciso.

Do you think that the UMI is defective, or could there be a problem with the hardware wiring/configuration? What is the best way to determine this?

[Giridhar_Rajan]

Hi GregH,

The best way to solve this problem is to first find out, whether the card is faulty or the umi is faulty. The method is as follows.

Take a blank PCB and connect 68 connectors to it. Get a 68 pin connector crimped to a 68 core cable at one end that fits into the PC. The other end of the cable has loose wires. Now assign ferul numbers to each cable from 1 to 68 and connect each of these to the connectors in the PCB. Now check the voltage levels at which ever pins you want. If you see a voltage, then you can replace your UMI and if you dont, then you can replace your card. I've tried this when my ADC on the motion controller was not working and found that the card was faulty. Be careful before trying it. I tried this under the guidance of a motion control expert. If you are not sure then you can send it to NI for checking or contact a field engineer in your location.

Regards,

Giridhar Rajan

Automation Engineer, Design

Cruiser Controls

Mumbai, India

[M0Reng]

Hello, 

GregH - do you have solution for this? i have SAME problem and trying to solve it for long time,

please reply if you can, i really appriciate your solution here.

any help is most welcome here

Thanks,

MotiM

[Tapan_Mojidra]

If you have Viso = 24v then you will get output voltage for Enable axis of 24V logic,

For low  it will be min. 0v to maximum 2.0v
For high it will be  min. 2.5v to maximum Viso.

Your drive may be TTL (0-5v) logic level, if it is so, connect 5v supply at Viso instead of 24v.