Ratio between value at different instances. Part of bachelor thesis.

[Peter Nachtwey]

it's for a master's thesis guys. how do you make sure the pressure has stopped dropping with 99% confidence?

 

[shooter]

what have you made so far, and what programtype are you using.
send a pdf and we will give an answer to you.
start with a simple I/O test to get confident with PLC.

 

[Erik&Robin]

I don't think noise will be a problem. We are using CX-Programmer. We have looked on using Shift Register, triggered by a pulse, which will sample from the analog input to DWORDS and use basic arithmetic blocks to compare the first sample with the last. That way we will always compare the difference in pressure drop the last 5 min, without taking into account the pressure stabilization phase.

I made a sample program in easySoft to show you what I'm thinking (A program i'm much more familiar with, but unfortunately the easy PLC won't be sufficient.) easy800_Shift_register.e60

Hopefully this will work with the Omron. We will get the PLC (CJ2M) in about a week, and will be able to test it then.

@Erik&Robin:
How do you intend to document the check?
A certificate with a printout of the drop curve?

This is also a part we have not yet fully solved, but we are thinking of using a DAQ which is triggered by the PLC to start logging the entire pressure test. We also considered the possibility to log directly onto a SD card or similar on the PLC as a .CSV file, but i guess this would be difficult if it's even possible.

Robin

 

[osmanmom]

Cj2m