How to control PIC with output signal

[Maciekdp]

Hello,

I have a microcontroller, which enables a servo-amplifier when it sees a square wave input (0 to about 5v) at a frequency on the order of 5Hz or so.  The microcontroller works when I  generate this square wave by flipping a switch manaully.  It does not work when I use a square wave which I generate in labview (either digital or analog output).  My card is a 6259M with BNC2120.  Does the DAQ output need to be somehow conditioned for it to work?

Thanks

Maciek

[AdnanZ]

Have you used a multimeter to see if you are getting a proper output from the DAQ card?

[mallorim]

Hello Maciek,

There are two things to check:

1. That the 6259 M-series card is outputting the signal correctly.

He makes a good point about testing the output of the M-series card with a DMM or another acquisition device to ensure that the signals are being generated properly. How are you generating the outputs? Are you running an NI LabVIEW example program or code you wrote yourslef? Is this a USB, PCI, or PXI card?

2. The second thing to check, after we verfied that the 6259 is in fact outputting, is that it is capable of outputting a signal that the microcontroller will accept.

What is the current draw of the microcontroller? If you look at the 6259's specification page, the analog output is only capable of driving +/- 5 mA. Can you better characterize the switch's signal? What is the input impedance of the microcontroller?

Regards,

Mallori M.