Vert Good! So much easier (and cheaper) than when I was in the high vacuum business back in the 1960's. I think we had as many as 3 instruments to cover down to 10-5 microns and we couldn't even power up the finest one in a coarse vacuum without destroying it.
Nice project. I have done similar stuff fo straingauges. Two comments. First the ads 1115 only gives you 15 bits the way you use it. If you want the 16bits you need to level shift so that half if the neasuring range sits at about 2.5V than you can use differential reding witch gives you the 16bit. This has another advantage, that in differntial mode the ads1115 uses a commenmode filter for the measurements so all the commen noise is filtered out. Second you are using the adafruit library and a single read. The ads1115 can work at different sample rangel. In my experience it makes a great difference what sample range you use because it decreases the noise a lot. So use the lowest samplerate 1/s for best resolution. Use averaging in the arduino code. In you code I have not see wicht samplerate the library uses so you might loss up to two bits of resolution there
Thank you so much. I have a Pfeiffer pirani gauge (TPR 270) with the same pins design. My measurement unit is not working and your video saved our experiments.
First off, great project. Subsequently, I would have a question about pin 1 (identification), what is this pin for? And also if I look right, pins 5 and 6 are connected and form ground? thank you for answer
Just subscribed. Great video! One question I had is in your voltage divider, how do you compensate for the resistance of the voltage measurement ADC itself? Or did you just estimate it at infinity?
Thank you! Appreciate it! Yes, I just estimated it at infinity. I know that's not the right way to do, and I am thinking about calibrating it. But since the pressure readings are reasonable, I will leave it as is for now.
As far as I know a calibration of the adc resistance is not necessary in this case as the viltage is provided by an instrumentation amplifier inside if the sensor. That will keep the voltage konstant as long as it can provide enough current. So the 500k input impedance of the ads1115 is good enough. If you would measyure the h bridge of the sensor directly that would be a different matter
Great project but your divider should have the same substrate... In other words not two separate resistors, but two resistors within the same package (such as SIP or DIP resistor packs).
What do you need it for? I used a bmp280 for pressure measurement. I think I got it reading down to 40pa which is lower than it's rated. But it was better than my analogue gauge. I have nothing to compare accuracy with but it was repeatable. The bmp180 would only read down to about 28000pa. Which reminds me I need to fix my vacuum pump motor.
Is there any chance you could help me with a project just like this? My pins are a bit different but almost the same, but my pins are 1 - Transmit RS , 2 Recieve RS, 3 - Power + , 4 Power Return - . I love your setup and would like to duplicate for use in a Neon Studio where I will be getting down to 1 Micron. I would love to work with you on this if possible, and I can compensate you for your time.
What model of gauge do you use? In most data sheets you can find the pinout. If you wait a few weeks there will be a new video about an updated version of this controller with the schematics for the pcb and new software.
Thank you, I didn't see this message@@AdvancedTinkering, I have a MKS901P gauge. I will be looking forward to the newest video as I will be doing this project soon. Thank you!
Thank you! I did not create a circuit diagram. It is a standard circuit for the ADS1115 and I just used a voltage divider to reduce the voltage. Depending on the sensor you may not even need a divider. I will upload the code to my github soon and post the link in the description.
