Just asking cos pressure + heat is a bomb by nature..
2 Likes
That is true! but I am only speaking about the range between 1000 hPa and 1200 hPa
so from 1 bar (atmospheric pressure) to 1.2 bar (0.2 bar overpressure - if - the conditions are unfavourable)
speaking of pressure...
Is this the correct way to calculate pressure from the voltage in ADS1115?
spec sheet says: VOUT = VOFF + (sensitivity x P)
Vout is measured with ADS1115
Voffset is 20 mV
Sensitivity is 1.2 mv/kPa
P is the desired value we need to calculate (in kPa)
So I thought P=((V_out-20)/1,2) in kPa
But I feel like I am missing something...
[{"id":"40f5c6c11104d810","type":"ads1x15_i2c","z":"6bd58bfbd46a21f9","property":"payload","name":"","i2c_device_number":1,"chip":"0x01","i2c_address":"0x48","inputsForChannel":"differential","singleEndedChannel0":true,"singleEndedChannel1":true,"singleEndedChannel2":true,"singleEndedChannel3":true,"differentialChannel0_1":true,"differentialChannel0_3":false,"differentialChannel1_3":false,"differentialChannel2_3":false,"samplesPerSecond0":"920","samplesPerSecond1":"128","progGainAmp":"4096","x":890,"y":2780,"wires":[["6b76245c13fa40dc"]]},{"id":"8ae074915f170c71","type":"inject","z":"6bd58bfbd46a21f9","name":"","props":[{"p":"payload"},{"p":"topic","vt":"str"}],"repeat":"","crontab":"","once":false,"onceDelay":0.1,"topic":"","payload":"","payloadType":"date","x":720,"y":2780,"wires":[["40f5c6c11104d810"]]},{"id":"6b76245c13fa40dc","type":"change","z":"6bd58bfbd46a21f9","name":"change payload with differential value","rules":[{"t":"set","p":"payload","pt":"msg","to":"payload[\"/dev/i2c-1\"].ads1115[\"0x48\"].differential.channel_0_1.miliVolts","tot":"msg"}],"action":"","property":"","from":"","to":"","reg":false,"x":1150,"y":2780,"wires":[["4418c5a1e79eab36"]]},{"id":"4418c5a1e79eab36","type":"function","z":"6bd58bfbd46a21f9","name":"P=((V_out-20)/1,2) in kPa","func":"msg.payload = ((msg.payload - 20)/1.2);\nreturn msg;\n\n//P=(V_out-20)/1,2 in pKa","outputs":1,"noerr":0,"initialize":"","finalize":"","libs":[],"x":1450,"y":2780,"wires":[["c0d2cafdbc2cacba"]]},{"id":"c0d2cafdbc2cacba","type":"debug","z":"6bd58bfbd46a21f9","name":"","active":true,"tosidebar":true,"console":false,"tostatus":false,"complete":"false","statusVal":"","statusType":"auto","x":1670,"y":2780,"wires":[]}]
msg.payload = ((msg.payload - 20)/1.2);
return msg;
I developed the ads1115 node:
In this node you can set the read cycle time.
I have also add example for scaling in function node.
Select adc input range 256mV.
20..90mV=0..50kPa
var pressure = scale(msg.payload[0], 20, 90, 0, 50);
Hope, that help you.
Will keep that node in mind. First need to let everything work on the other node as i have more flows with that one used 
But thank you!
Any idea if I am missing something in the conversion with the ADS1115?
Still stuck on this. Is it better to measure this on an arduino? Has my ADS1115 any impact on the way I calculate it...?
This topic was automatically closed 60 days after the last reply. New replies are no longer allowed.
