Describe what you need to measure
State the medium and whether the application calls for gauge, absolute or differential pressure. Include the normal operating range and the maximum conditions the device may encounter. Specify the units used in your requirement.
For an existing installation, include the current model, nameplate details and the reason for replacement. A product name alone is not a complete replacement specification.
Confirm the complete signal path
Record the receiving PLC, controller or display, its accepted input and the available power supply. Ask the supplier to confirm the offered output, wiring, connector and cable requirements against that information.
When comparing a sensor with a transmitter, ask what signal conditioning, enclosure and display are included in each offer. Confirm the supplied assembly rather than assuming that the two names describe interchangeable products.
Compare the mechanical and documentation scope
Provide the connection standard, thread or flange details, wetted material requirements, temperature conditions and installation space. Include any drawing or photograph needed to identify the existing connection.
Request a model-specific datasheet and an explicit list of included accessories, test documents and exclusions. Review the proposed specification with the person responsible for the application before approving the order.