Pressure Range and Overload: What to Specify

Describe more than the normal value

Normal operating pressure is only one point in the duty. Record minimum pressure, maximum sustained pressure and credible start-up or shutdown events. Identify whether the equipment can see vacuum or pressure reversal. The instrument must be reviewed against the complete process envelope rather than the value observed during steady production.

Keep range and overload separate

The calibrated measurement range defines how pressure maps to the output. The overload limit is a separate specification and should be checked on the applicable data sheet. Do not use a generic percentage rule to establish overload capability for all WESIVO products. Process connection ratings and temperature conditions also need review.

Understand the accuracy basis

An accuracy expressed as a percentage of full scale is not a percentage of the current reading. Selecting a much wider range can change the absolute error relevant to the operating point. Ask for the definition and reference conditions of the quoted accuracy, including any effects relevant to the process, before comparing two specifications.

Agree the configured range at handover

Record the ordered range, engineering unit and output scaling in the instrument list. Check that the PLC or indicator uses the same lower and upper values. If the measuring range is later changed, update both the field device and receiving-system documentation and verify the resulting indication using the approved commissioning procedure.