Designing a DQMH-based Sequencer

[Tenru]

Hi Delacor team!

I’m building a LabVIEW application using the DQMH framework. The app acquires data (NI-DAQmx, VISA, TCP/IP) and controls power supplies and relays via the same protocols. I’m now working on the Sequencer module.

In the legacy app, each operation was an element of an array of clusters with: operation duration, setpoints (currents/voltages, relay on/off), transition conditions, monitored parameters with limits, repeat count, and a “goto line N”. This became hard to read and extend. For example, current was set in the step, while voltage/power were global pre-run limiters only. I’d appreciate advice on how to design the new sequencer algorithm.

I also need cyclic execution of step groups. Example: there are 36 steps in total; run steps 0–5 three times; then run steps 0–12 twice; then execute the remaining steps (12–36).

I’d appreciate guidance on:

1. Step data model.

2. Conditional transitions: best practices for “if parameter X goes out of limits → turn off relays/PSU or jump to step Y”.

3. Existing examples: open DQMH-based “sequencer” examples (UI + engine). When would NI TestStand be a better fit?

4. Storage: preferred profile format (CSV/JSON/XML).

5. Safety/interlocks: where to keep global limits, and how to implement atomic PSU+relay shutdown on out-of-limit conditions.

Old sequencer:

 

[Olivier-JOURDAN]

Hi @Tenru,

Thanks for using our framework for your LabVIEW development. It's great to see what developers can do with it.

Regarding your questions, it seems way too generic to reply here. Architecting an app requires knowing your constraints (technical ones, but also time to develop, lifetime of the resulting app, etc…).

For me, it seems impossible to give you a reply in a reasonable amount of time, and I guess that nobody here can do it.

That being said, designing an app is one of the most interesting things in our work.

May encourage you to dive more into your architecture and ask narrower questions.

I can also encourage you to contact and hire a DQMH Trusted Advisor company to help you design such an app. Some of them will be more than happy to assist you, and it could be an excellent way to learn from experienced developers.

[joerg.hampel]

To augment Olivier's great reply (which I completely agree with), perhaps an existing off-the-shelf solution can be a viable alternative. It will cost some money but also takes away some of the risk involved.

Have you looked at the DTS (DQMH Test Sequencer) at all?