Sensor Loops Overview And Wiring (B921C/B942/B942W Only) - Bosch B9512G-E Installation Manual

Control Panels
Extra power for keypads
The keypads draw different amounts of current whether idle or in alarm. Refer to the
installation instructions for each keypad for current draws. Refer to Power supply, page 36 to
determine the total power output requirements for the system.
Add B520 Auxiliary Power Supply Modules to support the desired number of keypads.
Auxiliary power wiring
Notice!
Any power supply powering devices connected to the control panel must also be connected
to a common terminal on the control panel.
If using the ground fault detection capability on the control panel with an external power
supply, ensure that the external selected power supply isolates its earth ground connection
from the negative side of the auxiliary power output. External power supplies that do not
isolate earth ground can cause ground fault conditions on the control panel.
9.1.7

Sensor loops overview and wiring (B921C/B942/B942W only)

The keypad detects three states (Open, Supervised, Short) on its sensor loops and sends the
conditions to the control panel. Each sensor loop has an assigned point number.
Use twisted-pair wire for the module sensor loops to avoid electromagnetic interference
problems. Run wires away from the premises telephone and AC wiring.
To wire detection devices to keypad inputs, connect them to the keypad terminals labeled for
COM, and 1, 2, 3, or 4. Wire resistance on each sensor loop must be less than 100 Ω with the
detection devices connected. The terminal strip supports 12 to 22 AWG (0.65 to 2 mm) wires.
Bosch Security Systems, Inc.
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