Hi there!
Is it possible to add an output limiter to the PID controller instrument like the one present in the Laser Lock Box ? I’m using it in a situation where negative tension could damage the instrument receiving the control signal. Curently, I need to manually clamp the signal using an external circuit.
Best,
Corentin
Hi Azercoco,
We unfortunately do not have a built-in voltage limiter with PID controller at the moment. However, if you have access to Multi-instrument Mode and Moku Cloud Compile on your Moku, you can build a custom instrument for implementation on Moku:Go or Moku:Pro.
In this blog post, you can find the Cloud Compiled voltage limiter in the second example, which should be sufficient for your application. The upper and lower voltage limits of each channel are set by two control registers. The VHDL code can be found here, you will just need to copy the code into a Cloud Compile project and compile for your Moku. The main thing to watch out for is that there is a conversion from bits to voltage when the signal is converted from a digital signal to the output analog signal. You can find the conversion summary table below.
| Source/Sink | Moku:Go bits/volt | Moku:Pro bits/volt |
|---|---|---|
| ADC | 409.4 | 2270.02 |
| DAC (50R) | - | 29925.0 |
| DAC (High-Z) | 6550.4 | 14962.5 |
| Inter-instrument | 13100.8 | 29925.0 |
If you have not used Moku Cloud Compile before, you can sign up for a free trial on our website and you can follow this getting started guide to compile the project.
Please do not hesitate to contact us at support@liquidsintruments.com if you have any questions or encounter any problems.
Kind regards,
Nandi
The blog and VHDL code links are failed. Could you send me a new link?
Venusjin, I have sent you new links in your other post, but I will copy them here for anyone else looking for a voltage limiter to use with their Moku:Go.