W ith an ERD you have severalinstrument in one.
It's an instrument designed totest components for which a response is expected at a given pressure.
The instrument applies a gradually increasing pressure to the test part, until the expected event occurs, producing an electrical contact closure.
It checks that the pressure is within the specified limits and releases the pressure. Its design allows it to be used for on-line testing of production parts.
It's also a flow tester.