Page 47 - PNEUMATIC SYSTEM INSTRUMENT

Therefore, to avoid faulty connections, all the inputs and outputs of a

valve are identified.

A numbering system is used to designate directional control valves

and is in accordance with ISO 5599 (Draft). Prior to this a lettering

system was utilized and both systems of designation are presented in

Table 7.2.

Table 7.2: Directional Control Valve, Ports and Positions (ways).

Port or Connection ISO5599 Lettering System

Pressure port 1 P

Exhaust port 3 R (3/2-way valve)

Exhaust ports 5, 3 R, S (3/2-way valve)

Signal outputs 2, 4 B, A

Pilot line opens Z (single pilot 3/2
12
flow 1 to 2 way)

Pilot line opens
12 Y (5/2-way valve)
flow 1 to 2

Pilot line opens
14 Z (5/2-way valve)
flow 1 to 4

Pilot line flow
10 Z, Y
closed

Auxiliary pilot air 81,91 Pz

30