Polling Loop Limitations; Polling Loop Connections - ADEMCO VISTA-120 Installation And Setup Manual

Polling Loop
Limitations
When running polling loop wires, they must not be run within 15 cm of AC mains
voltage, telephone or intercom wiring. Since the polling loop is carrying data
between the control panel and the devices, interference on this loop can cause an
interruption of this communication.
interference on the intercom or phone lines. If this spacing cannot be achieved,
shielded wire must be used. (Note that the maximum total wire length supported is
halved when shielded wire is used.)
2. Wire each device to the polling loop, making sure to use correct polarity when
making connections (refer to the device's instructions).
3. Note the polling loop devices that have DIP switches on them. Set each
device's DIP switches for the zone number you are assigning it. Refer to the
device's instructions
manual when setting addresses.
Certain polling loop devices, such as the 998MX, 4278EX-SN, 4959SN,
4939SN and 4191SN, do not have DIP switches. Instead, they have internal
serial numbers which must be "enrolled" by the control during #93 Menu
Mode Zone Programming.
BASIC POLLING LOOP CONNECTIONS
VISTA-120
When in a star configuration, no individual run can be longer than the table indicates,
and the total length of all the sensor star runs, combined, cannot exceed 1220m. If
using unshielded wire in conduit or shielded wire, the maximum is 610m. If longer
wire runs are needed, a 4297 Polling Loop Extender Module must be used.
The built-in polling loop has the following limitations that must be observed:
• The maximum allowable current drain from the polling loop is 128mA. Refer
to the POLLING LOOP CURRENT DRAIN WORKSHEET (found in the
FINAL POWER-UP PROCEDURE section) for current drains of various
polling loop devices. If device drain totals more than 128 mA, a 4297 Polling
Loop Extender Module is required.
• The 4297 Polling Loop Extender Module may be used to provide additional
polling loop current, to extend the polling loop wire run, and/or to provide
individual, electrically isolated polling loops. Refer to the 4297 Polling Loop
Connection diagrams later in this section.
DO NOT use the 4197 Polling Loop Extender Module with the VISTA-120.
• Regardless of current drain, no more than 64 DIP switch devices or 119 serial
number devices can be connected to the polling loop. Installations which
require up to 119 zones using DIP switch devices will require the use of zone
expanders (4190WH and/or 4208), which allow more than one zone on each
expander. Otherwise, a 4297 Polling Loop Extender must be used.
The polling loop can also cause outgoing
or the DIP Switch Tables found at the end of this
BUILT-IN POLLING LOOP
+
-
Figure 12. Polling Loop Connections
}
2- WIRE RUNS SHOWN IN
A STAR CONFIGURATION
– 25 –