D8125 | Installation and Operation Guide | 4.0 Installation
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Bosch Security Systems B.V. | 2020.04 | F01U036298-15
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4.2.5 Wiring Data Expansion Loops to POPEX Modules
There are two positive (+) and two negative (-) data expansion loop terminals on each POPEX module. Follow
the procedure below to connect the data expansion loops to the D8125 POPEX Module (refer to Figure 3).
Remember you can only connect a maximum of 119 POPITs to one D8125.
1.
Connect the positive (+) Data terminal from the first POPIT on the data expansion loop to one of the
D8125 module’s positive (+) terminals.
2.
Connect the negative (-) Data terminal from the first POPIT on the data expansion loop to one of the
D8125 module’s negative (-) terminals.
4.2.6 POPIT Sensor Loops
The number of normally-open and/or normally-closed detection devices each sensor loop can supervise is
limited only by the resistance on the loop. Resistance on each sensor loop must be less than 100 Ω not
including the End-of-Line Resistor.
Certain UL and NFPA applications may limit the number of detection devices. Consult the appropriate UL or
NFPA standards.
Terminate each POPIT sensor loop with a 33 kΩ End-Of-Line resistor.
Bosch Security Systems recommends you use twisted-pair wire (six twists per foot) in all POPEX/POPIT
installations for both the data expansion loop wiring and the POPIT sensor loops. Run wires away from AC
sources to prevent AC induction.
