D8125 Operation and Installation Guide
D8125
Page 18
© 2004 Bosch Security Systems, Inc.
74-04247-000-N
Installation
M axim um Length of A ll Data
Expansion Loops Com bined
AW G (m m )
Length
Ft. (m )
22 (0.8)
1,800 (549)
20 (1.0)
2,890 (881)
18 (1.2)
4,600 (1,402)
16 (1.5)
7,320 (2,231)
14 (1.8)
11,650 (3,551)
3.1.3
Wiring POPITs to the Data Expansion Loop
Use one 2-wire data expansion loop or distribute the POPITs on up to three
loops. Setting DIP switches on the POPIT modules assigns them to point
numbers. Refer to Section 3.1.6 POPIT Module Point Assignments.
Determine the required wire gauge for each data expansion loop using Table 4.
3.1.3.1
Combine data expansion loops
The maximum lengths shown in Table 4 are for all data expansion loops
connected to the same POPEX module combined.
Before installing the POPITs, make sure the resistance on the data expansion
loop is no more than 40
Ω
.
3.1.3.2
Wiring POPITs together
Do NOT connect POPITs to each other in series, or with a T-tap. Doing so may cause random missing POPIT
conditions. Follow the procedure below to connect POPITs to one another in parallel.
Figure 3
shows a typical
configuration.
1.
Connect the positive (+) Data terminal from one POPIT to the positive (+) Data terminal on the next POPIT.
2.
Connect the negative (-) Data terminal from one POPIT to the negative (-) Data terminal on the next POPIT.
3.
Repeat steps 1 and 2 to connect all POPITs to the expansion loop. You don’t need to wire the POPITs in any
particular order on the loop. The switch setting on each POPIT assigns it a point number, regardless of its
physical location.
Three inch clearance for tampered POPITs:
Mount tampered POPIT Modules at least 3.0 in. (76 mm) apart to prevent the
tamper magnets from interfering with each other.
3.1.4
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 on the D9412/D9112 and 67 for the D7412/D7212.
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.
3.1.5
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 the 33 k
Ω
End-Of-Line resistor (D106F) included with each POPIT.
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. If you suspect a noisy environment, use shielded cable.
Table 4: Data Expansion Loop
Wire Specifications
