Using a cDAQ to control a stepper motor

[pacmann]

Hi,

I am relatively new to LabView. I am designing a program to control a stepper motor. I have attached a copy of my VI below. Basically I am trying to send a set of pulses from the DAQ to the stepper motor driver (L298n) and then get the driver to move the stepper motor.

The pulses that I am trying to send are.

1000

0010

0100

0001

I have tried this with an Arduino and it works just fine, however the stepper seems to jam when i try it on the DAQ.

Any help would be greatly appreciated.

[BertMcMahan]

Please attach a VI Snippet/image of your code, not everyone has LV 18 yet.

[pacmann]

Hi BertMcMahan,

I have attached a picture of the VI and a corresponding block diagram. It works for longet time delays but the moment I start to reduce the delays everything starts to go wrong.

[paul.r]

What is the point of the multiple loops? 

You are writing to all four DAQ assistant outputs randomly, with no synchronization between the two loops. Just use one loop - use dataflow to enforce the DAQ write timing. 

[pacmann]

Okay, will try that and see how it goes.

Thanks

[BertMcMahan]

I'd *strongly* recommend not using DAQ assistants and coding it directly. If you MUST use DAQ assistants, just use one, not four, as they can become desynchronized easily.

[BertMcMahan]

Thinking about it again... I bet your four assistants are the problem. With no way to enforce which one fires first, your step/direction pulse pattern won't generate properly. Use only one assistant and it'll probably work fine.