Hydractive Electrovalves rebuildable?

[ekaftan]

Sorry ekaftan, if you were local to me I may have been able to help

OK. I just thought I could send you money and you could ship it to me...

I'll keep looking. Thanks.

[PIT]

Hi Citro-friends

I'm going to investigate my electrovalves for problems, so I wanted to build an activator, so I can activate each valve whenever I want, even with running engine, so the system is full with pressure everywhere and so on.
So I made a small PCB with controller to make a 12 volts for 0.5 seconds and then a 1kHz PWM with 25% duty cycle.
But before connecting it to a valve, I decided to measure with oscilloscope the signals in the car. And here is the surprise 5 Volts max level and 6 Volts peak to peak when the signal is 1kHz PWM (the signal goes down to -1V)
https://www.dropbox.com/s/cow63d57urokv ... 192108.png" onclick="window.open(this.href);return false; - the start pulse
https://www.dropbox.com/s/jx9xvx1jr3a39 ... 190055.png" onclick="window.open(this.href);return false; - duty cycle measured here
https://www.dropbox.com/s/e1eu5dnkkvrfy ... 191745.png" onclick="window.open(this.href);return false; - peak to peak measured here

I did these measurements on two cars. Same results.

Any suggestions about this?

[CitroJim]

Waveform looks normal enough to me... I must admit I was initially expecting a 50:50 MS Ratio but after looking at many I know this is normal.

Here's one I took using an old-scool 'scope. Y sensitivity set to 5V/Div as can be seen on the 'scope itself..



I'd not trust that fancy software 'scope. Get a real 'scope on the job!

Using an AVO (proper analogue multimeter with a mechanical meter movement) you'll see about 3-4V measured... A very rough RMS. That'll confirm or otherwise what your 'scope is saying.

[PIT]

Thanks for the quick reply!
That was one of the things I was thinking. But couldn't find a reason why the USB 'scope should measure different values...
I'll find and try with a real one

[Hell Razor5543]

A proper scope shows you what is actually happening. A PC scope sometimes shows you its' interpretation of what is happening. This is not always the same.

[CitroJim]

A proper scope shows you what is actually happening. A PC scope sometimes shows you its' interpretation of what is happening. This is not always the same.

That's very well put James. People laugh when they see me get my old trusty AVO out when I need to measure volts or amps but you know real volts or amps is making the meter movement read something and not some software wizardry...

I do now often use a decent digital multimeter but it's very recent and only since I got my hands on a high-quality Fluke one I can trust a little. I always use an AVO on my vintage wirelesses though. There's no place for modern digital stuff there!