Burkert Type 8681 - Manual (Page 78)

78
Maintenance, Troubleshooting
18.2. safety positions
safety positions after failure of the electrical or pneumatic auxiliary power:
Operating mode process valve design
safety positions
after failure of the auxiliary power
electrical pneumatic
up
down
single-acting
Control function A
air opening •
spring closing •
down down
up
down
single-acting
Control function B
air closing •
spring opening •
up up
up
down
double-acting
Control function I
air opening •
air closing •
not defined not defined
By default, the control head is equipped with solenoid valves in circuit function design C
(Circuit function C: 3/2-way valve; closed in rest position, output A unloaded).
If process valves with several switching positions (e.g. double-seated valves) are connected, the safety positions
of the individual drives can be viewed according to the same logic as for a classical one-seated valve.
safety positions after failure of the bus communication:
AS Interface:
If the watchdog is activated (default), behavior corresponds to the event of a failure of the auxiliary electrical
power, i.e. all solenoid valve outputs are set to "0".
DeviceNet:
See chapter " 12.12.1. Configuration of the Safety Position of Solenoid Valves if Bus Error".
english
Control Head Type 8681