Specifications

Diagrams are for reference only.

Consult the appropriate installation sheet for wiring details.

REFERENCE SECTION

SIGNATURE DATA CIRCUIT MAXIMUM WIRE LENGTH CALCULATIONSSIGNATURE DATA CIRCUIT MAXIMUM WIRE LENGTH CALCULATIONS

SIGNATURE DATA CIRCUIT MAXIMUM WIRE LENGTH CALCULATIONS

QS1, QS4 and EST3

Circuit resistance and capacitance determines the maximum length of a Signature

data circuit. Circuit resistance affects the wire length of the longest circuit branch.

Circuit capacitance affects the total amount of wire that can be used on the circuit.

Note: The design of the Signature data circuit must not exceed either of the two

measurements.

There are no restrictions placed on the wiring used for the Signature data circuit.

Longer wire runs may be obtained using standard (non-twisted, non-shielded) wire

pairs.

Several factors influence the maximum allowable branch length:

• Wire gauge and type

• Number of Signature detectors and modules installed on the branch

• Number of SIGA-UMs configured for 2-wire smoke detectors installed on the

branch

Determining the maximum allowable branch length

The maximum branch length is the wire distance measured from the Signature

controller module to the last device on the longest circuit path as shown on the next

page.

To determine the maximum allowable length of a Signature data circuit branch:

1. Identify the device located farthest from the Signature controller.

2. Determine the number of Signature detectors, modules, and SIGA-UMs

configured for 2-wire smokes that lie on the same conductive path between the

device identified in step 1 and the Signature controller.

3. Calculate the number of detector and module addresses. Some Signature modules

require two addresses.

4. Determine the size of the wire used to construct the circuit.

5. Find the maximum allowable wire distance for the longest branch in the lookup

tables as follows:

If no SIGA-UMs are installed, use Table C-2

If 1–5 SIGA-UMs are installed, use Table C-3

If 6–10 SIGA-UMs are installed, use Table C-4

If 11–15 SIGA-UMs are installed, use Table C-5