Is there an example *.VI that works as an actual o-scope? Meaning will it take measurement from outside signals...see details...

[Glendinning Marine]

here it is...I've got a PWM signal being generated by a electronic engine control that my company designed and mfgs. I'm using the following fieldpoint hardware FP-1000, FP-AI-100 as monitors during environmental testing. The EEC outputs several voltage signals, the majority being DC voltages, for the exception of two PWM signals. the FP-AI-100 works out great due to the exact number of channels available matches the required signals to be measured during testing. I measure the PWM signals currently by taking a voltage measurement and converting it into a duty cycle mathmatically. But I was just curious if LabVIEW offered a VI that would ta
ke measurments just like an actual o-scope. Using the FP-AI-100 of course.

I searched the LabVIEW example data base and found the 1 Channel Simple Scope.VI and the 2 Channel Oscilloscope.VI but when I ran them I got an ERROR-10401 occured at AI Group Config. not sure what that means so I want guess.

If somone would let me know if there is such a VI or how to use the above VI's to accomplish reading a PWM signal I would appreciate it

[Aaron_G]

The LabVIEW examples that you found are written assuming the use of DAQ devices and the NI-DAQ driver. FieldPoint does not use the NI-DAQ driver and thus the examples do not work. Another problem is that with DAQ devices, you can create timed acquisitions, e.g. you can specify a sampling rate and number of sample with which to acquire data. FieldPoint modules are not designed with timed acquisitions in mind. The IO modules will update their channels at a fixed rate, called the All Channel Update Rate, and place the result of the AD conversion in shared memory. There are no provisions for ensuring that every ADC conversion is actually read by a network module. Thus, a network module may read the data at a faster rate and return duplicated readings, or may mis
s readings. Either way, you can not guarentee a constant time reading between readings which makes Pulse Width measurements somewhat error prone, especially for higher frequency measurements. In your case, the FP-AI-100 has an All Channel Update Rate of 2.8 ms. The only network modules capable of reading the data that quickly (oversampling rather than undersampling) is the FP-20XX modules, and only when running an embedded program, not when transmitting the data over the network.

Regards,
Aaron