Accuracy of transmitters

[gsinstrumentation]

Dear all,

Being new to the field, I have certain doubts which I would like to clarify with the people in here. Please help.

Can someone explain to me whether the accuracy of a transmitter depends solely on the sensor / element or also on the transmitter itself.
The accuracy required which we mention in the datasheet (eg. 0.065% for a PIT) is with respect to the sensor accuracy or the transmitter??

Also, please let me know how this applies in the case of a load cell. Since we provide a least count value for the load cell, how does this affect the accuracy ??

Thanks in advance.

 

[danw2]

For process pressure transmitters, accuracy statements by the manufacturer

a) are for the output of the transmitter. The customers are concerned with useable accuracy, the accuracy that the transmitter provides, where the sensor element is only one part. In fact, 'smart' electronics can compensate for non-linearities in the sensor element.

b) are at reference conditions: 25°C (77°F) ambient and process

c) vary with turn-down
Most industrial process transmitter spec sheets have detailed formulae for determining uncertainty at conditions outside of reference conditions.

The elements that affect accuracy are linearity, hysteresis, repeatability, process and ambient temperatures and (for DP transmitters) static line pressure.

I'll let someone else comment on load cells accuracy