Where should a DP flow transmitter's high-pressure side be connected relative to the orifice tape?

The high-pressure side of a differential pressure (DP) flow transmitter should be connected upstream of the orifice plate. This configuration is critical because the high-pressure tap measures the pressure before the fluid passes through the orifice. The pressure difference created by the orifice plate between the upstream and downstream sides is what allows the DP transmitter to measure flow rates accurately.

By placing the high-pressure side upstream, the transmitter captures the full static pressure of the fluid before it experiences the differential pressure caused by the restriction of the orifice. This setup ensures that the transmitter can effectively convert this pressure differential into a flow signal that corresponds to the fluid's rate of flow through the system.

Connecting it downstream would not provide an accurate measurement, as the pressure would already be affected by the orifice. Therefore, proper placement of the transmitter is essential for accurate flow measurement and reliable process control.