PWM signal is going to 9423 and not the motor

[solimad]

I am trying to measure the PWM signal into a blower.  So I wired the NI 9243 in parallel to the blower and I am able to read the digital signal.  However, the voltage at 12V and the current at 3mA but the motor still won't get the signal.  Is there another way to make this work?

[ZKami]

If you disconnect the NI 9243, can you power the motor normally? Could you post a schematic of what you are working on? Have you measured the voltage at the connections to the motor? 

[solimad]

With the NI 9423 disconnected, the motor works normally.   I attached an oscilloscope to see the pwm signal.  With no 9423 connected, the signal had a 12 volts peak to peak.  Then when I attached the 9423, the pwm signal going to the motor dropped to about 1 volt peak to peak.  However, the 9423 was reading a 12 volt peak to peak signal.

[ZKami]

Hello,

Could you give me a schematic and also more information about why you have it wired up this way. I don't think I quite understand how it's wired up from your description. 

Also, here is a document about the current and voltage characteristics of the 9423
http://digital.ni.com/public.nsf/allkb/7C8EE3C395478645862573FC00783B08

The different current draws of your two devices may be the source of the problem. Have you been measuring current?