MKS 901p python controller

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Ameen Aydan
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MKS 901p python controller

Post by Ameen Aydan »

Hi all,

I was surfing Github and noticed this

https://gist.github.com/samyk/c62643918 ... 541f4d2a91

It's a controller that someone wrote for the MKS901p, a gauge that many are familiar with on this forum.

Hope you guys see it well!
AA
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Richard Hull
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Re: MKS 901p python controller

Post by Richard Hull »

Nice long code listing. I wonder what controller it was written for?? Github is a nice place for very useful accessory codings and libraries.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
Rex Allers
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Re: MKS 901p python controller

Post by Rex Allers »

... what controller it was written for??

Huh? The MKS 901p is a nice small vacuum sensor that works well in the typical fusor ranges of operational vacuum.
MKS-901p.jpg
There have been many posts about it on the forum. Search '901p'.

It takes DC power of 9-30V -- I usually have used a 12V battery to feed mine. There's one pin that provides an analog voltage output that is a log of pressure. More usually, there is an RS232 style serial com interface. You send commands and it reply's with results. So for pressure readings, a digital value like 2.93 E-3 Torr. On the serial interface you can configure things like...
Units: Torr, mbar or Pascal
Gas: Nitrogen, Air. Argon, Helium, Hydrogen, H2O, Neon, CO2, Xenon
You can also set the analog output curve to emulate many industry common devices,
ex: Inficon MPG400 / Pfeiffer PKR251 emulation

A very nice device. Still listed on ebay at <$50. Finn developed a small board to plug in and display readings from a 901p.

So I'm not very familiar with Python language, but no doubt the Github listing is to talk serial with the 901p. No controller needed. It is all in the sensor.
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Richard Hull
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Re: MKS 901p python controller

Post by Richard Hull »

Most controllers, as written, are to use the data belched on of the device and display it to the human eye. The hard work is truly done in the device. Therefore the DC output can be used by itself, but it is tough to display in a fashion that does require a bit of fancy dancing if just using a volt meter.

The typical capacitive electronic manometer gauge is much simpler to power and use to a direct reading voltmeter. The expensive controllers for Capacitive vacuum gauges are nothing more than a +/- 15 volt DC supply and a common voltmeter in a box!! No need to buy a controller with them. Any dolt can make one for under $30.00. An electronics buff with a simple junk box can make one for free.
Capacitive vacuum gauges are typically very expensive but are true displays of the real pressure of all gases with no need to figure or correct the reading for gas type like a TC or Piranni gauge.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Ed Meserve
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Re: MKS 901p python controller

Post by Ed Meserve »

I'm a big fan of these little gauges.

Some of these 901 gauges also have a 0-10V proportional output for pressure. I setup a 100uA meter to display the voltage which I then do the math to find the pressure; P=10^(Vout -6).

viewtopic.php?f=11&t=13474

Ed
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