The schematic diagram below shows the single block and bleed valve manifold.
Removing the DP transmitter (DPT in diagram above) is very easy. Simply close the block valve and open the bleed valve to vent process pressure to the atmosphere. The DP transmitter is already out of service.
Putting the transmitter back into operation is also easy. Ensure that both bleed and block valves are initially closed. Then open the block valve and the transmitter is back to service.
Also Read: 5 Valve Manifold Operation