Polling Loop Zones 10-128; Polling Loop Overview; Common Characteristics Of Polling Loop Zones - ADEMCO VISTA-120 Installation And Setup Manual

2-Wire Polling Loop Zones 010-128
This section provides the following information:
Polling Loop
Overview
Common
Characteristics of
Polling Loop Zones
Wiring/Addressing
RPM Devices
–24–
SECTION 7

• Polling loop overview

• Common characteristics of polling loop zones

• Wiring RPM devices to the polling loop
• Addressing RPM devices
• Polling loop limitations
• Checkout procedure for polling loop zones
You can expand the system from the basic 9 zones to up to 128 zones using the
built-in 2-wire polling loop. Each device that is connected to the polling loop has
the ability to communicate with the panel about its status. These devices are
called RPMs (Remote Point Modules). The polling loop provides both power and
data to the RPM zones, and is constantly monitoring the status of all zones
enabled on the loop. The maximum current drain of all devices on the polling
loop cannot total more than 128mA (unless using a 4297 Polling Loop Extender
Module).
Refer to the list of compatible devices at the end of this section.
Polling loop zones have the following characteristics:
• Must use RPM (Remote Point Module) devices
• Supervised by control panel
• Individually assignable to one of 8 partitions
All devices on the polling loop must be wired in parallel to the [+] and [-] Polling
Loop terminals of the control panel (24 and 25, respectively). You can wire from
device to device, or have multiple branches connected directly to the control panel
in a star configuration. Be sure to observe proper polarity.
Although each polling loop device is wired in parallel, each device has its own
unique zone number (or group of zones if it is an 8- zone expander). On some
devices, this is determined by the setting of DIP switches. Other devices have a
built-in unique serial number which must be "enrolled" into the control using a
desired zone number. Whenever possible, serial number addressing mode should
be selected instead of DIP switch addressing mode for improved processing speed.
Set up the polling loop as follows:
1. Run wires to each device on the polling loop using the guidelines in the
following table for maximum wire runs per wire size Twisted pair wire is
recommended for all wire runs.
Maximum Polling Loop Wire Runs
Wire Size Max. Length
0.64 mm O.D. 198 m
0.81 mm O.D. 290 m
1.0 mm O.D. 457 m
1.3 mm O.D. 732 m
Maximum total wire runs combined must
not exceed 1220m regardless of wire size
(610m if shielded wire is used).