Agilent Technologies 1100 Series Reference Manual page 76

Theory of Operation
How the Electronics Work
and solenoid valve. The status lamp turns red and the error output on the
remote connector will be activated.
The error output at the remote connector provides a contact closure
(potential free open collector maximum load 35 V DC/50 mA) as long as the
error condition is active. The error condition is set (closed) when the status
light shows the error condition (red).
The continuous mode overwrites all other operation modes of the degasser.
When activated (switch SW1 on the electronic board or via the auxiliary
cable) the vacuum pump is forced into continuous mode and is turned on as
long as the degasser is switched on.
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