Long story short, I dove into some irrigation repair work that I am familiar with, but this troubleshoot job took some skill. System is a 2-wire that uses digital over analog, with decoder modules placed in the field to tell valves to turn on.
Main issue is, though job is complete, is even though I bought the CM2100B (love that meter!!!), and it has a VFC mode which as I recall is variable frequency mode, but no clue of the range, but I am very certain it could not see the current, or ignored it, on a solenoid that should be pulling about 40mA. I know the solenoid worked fine, I was just testing the meter.
At some point, I need to be able to get some current data of the power going to a solenoid. It probably doesn't have to be accurate, and I am just fine using a CT and just reading a voltage response on that as a sign that current is moving.
I think every OEM wants to hide their tech but I think the one I worked on runs about 1700hz, but I may stop in with a scope to see some stuff... I do know that control has a mode which flips the field to simulated 24VAC mode just so you can use a meter in the field. It works and my Fluke graphing DMM could then resolve that craptastic wave form. It was a choppy 30V and 62hz, but I could read it.
So the goal is something cheap, I can clamp on a small wire without breaking connection, and get a response from about 40mA current. Usually things are either good or bad so it could damn near be a red light/green light type of deal. Problem is very few meters will show current on these digital systems.