How can I control 3 stepper motors w/ amplifier by sending TTL pulses from DIO96

[Roman Z]

We have NI PCI-DIO-96 board and we have 3 stepper motors with amplifier and encoders. We want to control the motors by sending TTL pulses directly from the DIO-96 board to the amplifiers. Is this possible? What would you recommend if this is not a good approach? Thanks in advance.

Roman Zeylikovich

[mhaag]

Roman,

Thank you for contacting National Instruments. While using a motion controller would be the recommended approach for any type of motion application, you may be able to use your DIO board to generate a TTL pulse train to control the step and direction inputs of your drive and motor. You will need to make sure that the current sinking and sourcing specification for the DIO-96 fits your stepper motor. That board is not designed to source very much current at all so this is one issue you will need to verify. Also, this board does not have any counter/timer logic that can handle quadrature encoder inputs.

Again, this digital device is probably not the best solution to control a stepper motor, but, depending on your hardware, could be configured to work proper
ly. The PCI-7334 is a low-cost stepper motion controller that can control up to 4 axes and is designed to easily accommodate these types of applications. You can browse through more information on our Motion controller boards at the following website:

http://sine.ni.com/apps/we/nioc.vp?cid=3809〈=US

Let us know if you have any more questions or comments.

Regards,
Michael
Applications Engineer
National Instruments

[Buechsenschuetz]

I agree with the previous answer. It IS possible to control a stepper motor (driver) with a pure digital I/O board. However, you will have to write all the routines yourself which are usually contained in the firmware of a dedicated motion controller. You will have to evaluate acceleration and decelaration profiles, encoder pulse capturing etc etc.

It is a bit similar to simulating a serial interface with digital I/O. It is possible to do that but there are other 'off the shelf' solutions which in most cases are more convenient to use. The same applies for controlling stepper motors with I/O boards.