DC switching board

RE: DC switching board

Jan Cumps — Sat, 04 Feb 2023 15:24:56 GMT

If your microcontroller supports TinyUSB, you may be able to port this firmware: [mention:a9f996e2a31e4a71948bfe8464ef4d84:f7d226abd59f475c9d224a79e3f0ec07]

The only files you'd need to change is the main file, to do the standard board bring-up of your controller.
And the gpio_utils header and source file, to use the gpio API of your controller instead of the pico.

You'd get a device that's SCPI compliant, and would be able to switch relays by the command DIGI:OUTP# 0|1

# would be your relais / channel
0|1 would be off / on

I may steal some of your design in return - to make a little switch board with a Pico.

RE: DC switching board

Andrew J — Thu, 02 Feb 2023 13:35:21 GMT

A while back I was playing around with a 4DSystems 4Duino board which has a built-in Arduino and ESP processor. One of the things I did was have the ESP processor serve up a web page that could accept SCPI commands from a user who attached to the board over WI-FI via a web address (internal network.) These were parsed and commands sent to the Arduino for processing, the response returned to the ESP which parsed and updated the webpage.

You obviously don't have the Arduino, but if you want the code it is easy enough to pull out the Arduino elements and see how the ESP can actually serve up a web page and process commands. Doesn't have to be SCPI of course!

RE: DC switching board

DAB — Sat, 28 Jan 2023 19:21:30 GMT

Nice build.

RE: DC switching board

Jan Cumps — Sat, 28 Jan 2023 18:55:03 GMT

"I could buy a Keithley 2000-SCAN board"

I bought a 2nd hand one. I don't have it yet. I'll share my learning path.

RE: DC switching board

dougw — Sat, 28 Jan 2023 16:50:03 GMT

Awesome project. I wonder if there are any screwless terminal blocks that would fit on the card.

RE: DC switching board

colporteur — Sat, 28 Jan 2023 16:15:58 GMT

Your post takes me back to the early 90's when our shop started using test equipment that could be programmed. I wrote scripts using the ED editor to perform semi-automatic audio testing. Measurement requiring impendance changes from high to 600ohms were common. Miss changing a setting at the audio got three db louder. Being responsible for moving the leads and letting the script take care of the settings was a joy.

The communication interface is a Keithley DMM6500. What would be involved in making it less proprietary?

Just a thought.

RE: DC switching board

Andrew J — Sat, 28 Jan 2023 10:10:26 GMT

Looks really interesting. I’d like to read more about it in some detail and see some more use cases if that’s possible.

RE: DC switching board

shabaz — Sat, 28 Jan 2023 07:08:53 GMT

Nice-looking instrument!

I had these suggestions:

(a) Maybe change the sense banana sockets to different colors for unambiguity, e.g. orange and blue instead of red and black perhaps

(b) spread them out, i.e make the board bigger, so that the connectors don't need to be so close. I don't think anyone would mind if the board was bigger.

(c) Either for all of the sense relays, or for a couple of them, have space for a footprint for normal relays too, so that users can choose themselves to solder in reed relays or normal relays in those positions. That way, the board can be used for injecting source signals/power as well as measuring. For source signals, the users would apply that to the sense terminals (orange/blue or whatever)

(d) If it's not already present, a temperature sensor chip on-board could be handy for recording ambient temperature

(e) A minor thing, perhaps either a row of LEDs at the front, or a 7-segment LED showing which connections are made could be handy. The LEDs seem to be in an inconvenient place, since they won't be visible in a testbed perhaps. I guess it could even be a separate small board with flat flex cable, to mount it wherever desired.

Anyway, these are just some ideas, maybe not important/relevant.