Data Acquisition (DAQ) and Control from Microstar Laboratories

Knowledge Base: Processing

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Q10025 Smooth transitions between measurements

Tags: Help, DAP, DAPL, processing commands, PIDRAMP, open loop control

Applies to: DAPL 3000

Under control of my PC host software, I need to send positioning commands to my system, allow the position to settle, and then take measurements. If I send a new output level directly to the D-to-A converter channel, this produces a severe jolt, and I can't be sure that the system has settled when I take measurements. Is there a way that I can produce smooth transitions without complicated processing in my PC host application?

You should try the PIDRAMP command. Though it was originally intended for smoothing the setpoint command levels for a closed loop control system, this command can also be used to drive an open loop control system directly.

In your processing command, define a PIDRAMP task that receives command levels directly from your $BinIn host communication pipe. When it receives a new output level, the PIDRAMP task expands that into a sequence of levels along a smooth, timed transition from the previous level to the new one. This can be used to drive a timed output burst configuration, or delivered directly to the converter port using a DACOUT processing command. You can select a transition shape and duration that gives you the best transition time and settling.


For more information about the PIDRAMP and DACOUT commands, see the Dapl 3000 Reference manual.