Designed as a new series of process instrument manifold for particular transmitter models. The coplanar manifold when assembled to transmitter has the advantage of compact size with ease for operation in minimum space, thereby eliminating several components in integrating the manifold to the transmitter. The coplanar manifold has two isolating valves, one equalizer valve and two vent ports duly plugged. The manifold dimensions illustrated are for standard 33 mm instrument centres but available for other centres. The direct mounting facility to the base of the differential pressure transmitter results in less leakage points and more accurate measurements.