Section 4: Design Considerations; Limits; Wire Runs; Eia-485 Wiring Specifications - Honeywell NOTIFIER ACS Series Manual

Annunciator control system

Table of Contents

4.1 Limits

The standard NOTIFIER EIA-485 circuit can drive up to 32 annunciators with expanders. One system can mix ACM-24AT, ACM-48A,

ACM-16AT, ACM-32A, and their expanders with other ACS devices such as LDM, TM-4, etc. An end-of-line resistor must be installed or

enabled on the last ACS device on the circuit. The number of annunciators that can engage in two-way communication depends on the num-

ber of addresses available with a given fire alarm control panel. The actual number of ACS devices that can be powered in a particular sys-

tem depends on the current available from the control panel's power supply. Refer to the installation manual for the particular control panel

for more details. For information on boosting the EIA-485 circuit signal or adding additional devices (not addresses), see the RPT-

485W/RPT-485WF Installation Manual.

4.2 Wire Runs

Communication between the control panel and ACS annunciators occurs over a power-limited 2-wire EIA-485 serial interface. This commu-

nication is supervised by the fire alarm control panel. Each annunciator/expander module also requires a power-limited 24 VDC power con-

nection. This power circuit is inherently supervised; loss of power registers as a communication failure at the control panel. The ACS can

also be powered from a power-limited and regulated remote power supply listed for fire-protective signaling use.

NOTE: (AM2020/AFP1010 installations only) SIB-2048A/SIB-NET can support two EIA-485 circuits, each capable of spanning 6,000 feet at

16 AWG. For more details, refer to Appendix D.

4.3 EIA-485 Wiring Specifications

Wire the EIA-485 circuit as shown in Section 5.5, "EIA-485 Circuit Connections". These requirements must be followed:

•

The EIA-485 circuit cannot be T-Tapped; it must be wired in a continuous fashion to function properly.

•

There is a maximum of 6,000 feet at 16 AWG between the panel and the last annunciator on the EIA-485 circuit (subject to your

system's power restrictions).

•

The wiring size must be a 12 AWG to 18 AWG twisted shielded pair cable having a characteristic impedance of 120 ohms, +/- 20%.

•

Limit the total wire resistance to 100 ohms on the EIA-485 circuit, and 10 ohms on the annunciator power circuit.

•

Do not run cable adjacent to, or in the same conduit as, 120 volts AC service, "noisy" electrical circuits that are powering mechanical

bells or horns, audio circuits above 25 V

•

If annunciators are to be mounted in a separate cabinet or powered by a remote power supply, see Figure 4.2, "Using Multiple Power

Supplies With the EIA-485 Circuit". For information on boosting the EIA-485 circuit signal or adding additional devices (not

addresses), see the RPT-485W/RPT-485WF Installation Manual.

All power must be turned off when connecting the annunciator.

4.4 Receive/Transmit and Receive Only Configuration

4.4.1 Receive/Transmit Annunciators

Annunciators that are configured to serve as full function annunciators can both receive status information as well as transmit commands to

the control panel. This allows the annunciator to remotely execute functions of the control panel in addition to displaying the status of the

system.

4.4.2 Receive Only Annunciators

For redundant annunciation of system points, annunciators can be configured as "Receive Only" annunciators. Receive Only annunciators

must be set to the same address as the annunciators they duplicate. Receive Only annunciators intercept information being transmitted to a

"Receive/Transmit" annunciator for duplication at an intermediate display location. When configured for Receive Only operation, they can-

not be used to send information to the system, and as a result are not supervised by the control panel. They cannot perform remote functions

such as Acknowledge, Signal Silence, or System Reset. Control switches on Receive Only annunciators can be used only for local functions,

such as lamp test. Wiring to Receive Only annunciators may be supervised by installing the modules "upstream" of fully supervised,

Receive/Transmit annunciators along the EIA-485 line (see Figure 4.1).

ACS Manual — P/N 15842:N3 5/4/2022