04-05-2015 01:44 PM
Hello,
I want to send an analog output signal that changes with time:
-Increase from 0-10 V at a rate of (3.2/7 = 0.4571) V/sec
-Wait at 10V for 2000 ms
-Decrease from 10-0 V at a rate of (3.2/7 = 0.4571) V/sec
Which function would work best for this purpose?
I was trying to use the triangular waveform, but am not sure how to use it in a while loop because it isn't working as expected.
I have a Volt-time array which can simulate the signal...if only I knew how to use that to generate my waveform.
I'm using a Measurement Computing DAQ (USB 3103) with 16 bit resolution. Not sure if you need max sampling rate for analog output, it isn't there in the manual.
Thanks,
Prafulla.
04-05-2015 02:05 PM
04-05-2015 02:12 PM
04-05-2015 02:25 PM
@mikeporter
The signal will be sent to a controller controlling the pressure in a hydraulic system from 0 to 5000 psi. I'll send an analog signal to the controller and the controller will send a PWM output to the valve.
The response time of the hydraulic system is very high, if I change the pressure by a 1000 psi, the flow takes about 2-3 seconds to stabilize, doesn't affect my application much though, as I don't need to control the pressure to a specific value. It just needs to go up to 5000 psi and back to zero and measure pressure-flow at equal intervals of time. The max pressure shouldn't exceed the rating though, which is almost always within +/-25 range of 5000 psi.
Thanks
Prafulla.
04-05-2015 05:39 PM - edited 04-05-2015 05:42 PM
@mikeporter
I'm trying to get the ramp pattern using a state machine.
Should my state change (from Ramp up to Hold high) when 22 seconds have elapsed (time-driven) or when the ramp function has ended (event-driven)?
How should I do either of them? I don't know how to check when the function has ended or how to measure absolute time inside a while loop.
Could you please provide an example VI for the same?
Thanks,
Prafulla.