UMI-7764 PCI7330 Voltage levels wrong

[Xolotl]

Hi, I’m using a combination of UMI-7764 PCI7330 for controlling steppers, in the past i was using a Gecko driver with configuration CC/CCW with not problems, recently i change for a new driver RMS technologies R208 that uses Direction/Clock the systems works just for few minutes and now a have a zero voltage all the time on  the direction output, the driver has a internal resistor of 440 Ohm to drive a optocupler for the input, but the direction channel fails on all the 4 axes available, i tried to use again the CC/CCW settings but the signal of the channel CCW goes just from 0 to .2 volts the driver don’t detects it as a pulse, is possible to reset the voltage levels of the UMI?

I upgraded to NI-Motion 8.2 to reset the board and upgrade firmware but the problem still.

[Jochen]

Hi,

the PCI-7330 provides open-collector outputs for the STEP/CC and DIR/CCW outputs which are pulled up to +5 V with a 3.3 kOhm resistor. Swapping between STEP/DIR and CC/CCW mode doesn't change the physics of the outputs, so this won't change the behavior.

In order to drive the optocouplers of your R208 you need to change the cabling a bit (an external pull-up resistor is required). For more details please click here.

Kind regards,

Jochen Klier

National Instruments