No output from PID (DBL Array)

[KFarries]

Hi,

I am new to Labview.  I am trying to simulate two PID loops simultaneously using the PID (DBL Array) as shown in the attached vi. However, the PID loop does not appear to produce any output.  I would be very grateful if you can point out the (foolish) error in my code!

Thanks in advance.

[GerdW · Accepted solution]

Hi KF,

there are several problems with your VI:

• the shift register is not initialized: so it starts as empty array and your PID will output an empty array when it gets an empty input array…
• the loop delay is given in ms, but the PID function expects a value using unit s: did you notice that red coercion dot?

See this:

One problem is solved, the other not…

Suggestion:

Instead of using BuildCluster to create the plots for your chart I would stick with array functions (BuildArray). This way your code is more scalable once you start to use more than two channels in your PID…

[KFarries]

Of course! Had looked all over for an example using the PID array but couldn't find one. 

Many thanks!