VOFA-L26-T32C-M-G14-1C1-...
Festo – VOFA-L26-T32C-M-G14-1C1-... – 1409NH English
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5
Function and application
5.1
Pneumatic linking
The safety function is achieved through two-channel pneumatic interlinking of two single solenoid
5/2-way valves within the control block:
–
Port (2) is only pressurised if both solenoid valves are switched to switching position (12) (circuit
symbol
Fig. 12).
Through the sensing of the proximity sensors (E1 and E2) at the solenoid valves (V1 and V2), it is pos-
sible to monitor the switching operation of the solenoid valves. This is done by means of a logic opera-
tion of the control signal and the signal change of the proximity sensor to check whether the piston
spools of the solenoid valves are reaching or leaving the normal position (expectations).
The pneumatic connection example (Fig. 2) shows the linking of the control block. It contains an up-
stream combination (series connection) of a pressure-regulating valve and pressure-relief valve. The
latter serves to protect the pressure-relief function of the pressure regulating valve.
1
2
3
4
1
Pressure regulators
2
Pressure-relief valve
3
Control block
4
Actuator
Fig. 2
Example of a two-channel pneumatic linking of the control block
