How to calculate maximum error?
How to calculate maximum error?
(OP)
Hi,
I am wondering how I can calculate the maximum error of a measurement chain.
If I have a voltage transducer with a accuracy of +-1%, which is wired to analogue input of a PLC (12 bit), what's the error of it?
The output of the transducer is 0-10V so as the input.
Cheers,
Lars
I am wondering how I can calculate the maximum error of a measurement chain.
If I have a voltage transducer with a accuracy of +-1%, which is wired to analogue input of a PLC (12 bit), what's the error of it?
The output of the transducer is 0-10V so as the input.
Cheers,
Lars





RE: How to calculate maximum error?
The general rule to add independent errors is RMS and that means error is sqrt(0.01^2 + 0.0005^2) or 0.01001, which corresponds to 0,01001 or 1.001% error, which means that you can forget about the influence from PLC resolution.
So, it is very important if your transducer's error is ten times or more. On the other hand, if your PLC isn't better calibrated than 1%, then your RMS error will be sqrt(1^2 + 1^2) or 1.4%. The maximimum possible error will be 1 + 1 = 2%
Then you have to decide if this is linearity only or offset plus linearity. And, then again, is your error refered to range, maximum value or actual value?
It is almost impossible to state what the error is without going into lots of details like that.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: How to calculate maximum error?
RE: How to calculate maximum error?
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.