Xtralis HeiTel CamDisc HNVR Product Manual page 21

HeiTel by Xtralis
Normally closed BS 8418
In the wiring variant Normally closed BS 8418 with two resistances a distinction is made between three
different states:
Not triggered: The figure shows the safe state (not triggered) of the detector line or the control input.
l
Camera alarm: If the "Normally closed" contact is operated, a camera alarm is activated.
l
Sabotage alarm: If the detector line is interrupted or shorted, a sabotage alarm is activated.
l
Error relay
The device configuration allows designation of integrated relays as error relays in order to report certain
operating states or malfunctions using dry contacts. The status of the error relay then always corresponds to
the status of the Logfile LED on the front of CamDisc HNVR:
Error if Logfile LED on, then error relay energised
l
No error, if Logfile LED off, then error relay de-energised
l
Examples for possible errors reported by error relay:
Faulty DSP
l
Faulty video decoder
l
Faulty clock module
l
Memory error
l
Note: If the Error relay is not in use and the Logfile LED is illuminated Red, this indicates system
information and notification of errors, such as system errors or video signal failure.
Sabotage protection
The error relay is pulled in idle - no error. Therefore the error relay can be used as sabotage detector, as it
automatically falls off in the event of power failure (e.g. caused by cut power lines). Depending on the error
relay wiring, an interruption of the relay line itself can be reported as well.
Note: There is a theoretical possibility that sabotage protection will not work if error relay switching is not
consistent with the operating mode.
26419_04
R
L
Control input
R
T
R =R =1,5 kΩ (±1%)
L T
CamDisc HNVR Product Guide
21