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Products: AO-8, AO-V-8, AS-P Smoke Control, Automation Server Smoke Control, DI-16, DO-FA-12, DO-FC-8, RTD-DI-16, UI-16, UI-8/AO-4, UI-8/AO-V-4, UI-8/DO-FC-4
Functionalities: Smoke Control
Product version: 2022, 2023, 2024

Central IO Module Installation

The Central IO modules all use the same model TB-IO-W1 terminal base model. You install the Central IO modules on the terminal base as follows:

  • Position the Central IO modules directly to the right of the AS-P/AS Server, starting with position 3 on the I/O bus

    Position 1 is for the PS-24V and position 2 is for the AS-P/AS Server.

  • Slide the first TB-IO-W1 terminal base to the left on the DIN rail and mate it together with the TB-ASP-W1 terminal base

  • Snap additional TB-IO-W1 terminal bases onto the DIN rail working toward the right side of the DIN rail

    Each TB-IO-W1 terminal base connects with the previous terminal base on the left.

action_zoom_plus_stroke TB-IO-W1 Dimensions

TB-IO-W1 Dimensions

Up to 30 Central IO modules (depending on I/O type) may be installed after position 1 holding the PS-24V and position 2 holding the Smoke Control Server. The Central IO modules are selected from the 17 models listed in this guide.

action_zoom_plus_stroke TB-IO-W1


All Central IO modules are powered by the PS-24V module(s). Be sure to observe the power budget of the PS-24V when adding Central IO modules to the configuration. The power load on a single PS-24V must be kept to 30W or less.

The accumulated power load (watts) required for the Smoke Control Server and the selected Central IO modules must be tracked to ensure the load on a single PS-24V is not over 30 watts. For more information, see Power Rating .

When the accumulated load reaches 30 watts, you must add another PS-24V on the bus.


The TB-PS-W1 terminal base used for mounting the PS-24V supply module consumes one of the 32-bus position addresses. Each PS-24V module reduces the maximum Central IO module count by one. The total number of terminal bases on a single I/O bus is 32 (counting the PS-24V, the Smoke Control Server and Central IO modules).

The Central IO modules extending from the right side of the Smoke Control Server communicate with the Server via the DIN rail bus achieved through the terminal base modules that create a backplane structure for power, addressing and communications. The connection with the Central IO modules is supervised by the Smoke Control Server and the loss of a module is reported to the Smoke Control Server managing the FSCS.

When the physical space along the initial DIN rail length is exhausted, you can use an S-Cable to connect to the end (right side) of the group of TB-IO-W1 terminal bases and extend down and to the left side to start another DIN rail segment of Central IO modules.

The S-Cable models S-CABLE-L-1.5M (1.5 meter length) or S-CABLE-L-0.75M (0.75 meter length) are used to extend the I/O bus up or down to another horizontal DIN rail.


Loss of data

A maximum of 5 S-Cables can be used to create the I/O bus structure.

Failure to follow these instructions can result in loss of data.

The input and output points provided by the Central IO modules are used to monitor and control equipment in the facility. When the inputs or outputs from a specific Central IO module are used in the smoke control application, the supervision of the communication with that module must be included in the summary fault supervision reported on the FSCS panel.


The individual inputs and outputs extending to the field from the Central IO modules are not supervised.


When the contact inputs (DI or UI) on the Central IO modules are used to receive/monitor the alarm output contacts from a Fire Alarm Panel, those connections must be wired in conduit for a maximum distance of up to 20 feet. See the discussion that follows on the Fire Alarm Panel for additional information.

Manual Overrides

The Central IO module models with a -H designation in the model number include manual override switches on their face panel. During installation, setup and commissioning of the system, these can be valuable tools. After the system is put into service, these switches become potential sources for inadvertent disabling of the system or a portion of the system. When the manual override switch is associated with an output point involved in smoke control, the status of the override switches must be supervised by the Smoke Control Server.

All Central IO modules are designed to allow the Smoke Control Server to read and monitor the status of the local manual override switches. The smoke control application in the Smoke Control Server must be programmed to generate a manual override FAULT indication if any of these switches are not in the AUTOmatic position.

The FSCS panel shall be designed to include a MANUAL OVERRIDE FAULT LED indication. The LED will be programmed to activate when any controller points participating in smoke control application have an override active (out of the AUTO position). Just as with the other equipment or communications faults, a manual override on an Central IO module will prompt the activation of an audible alert. If the SILENCE audible switch is used, the audible alarm must reactivate after 24 hours if the override condition persists. In other words, the manual override is considered a problem that cannot be allowed to persist. This is the same arrangement for policing and handling HOA override switches on the legacy field controllers on the MS/TP or Infinet 2 bus.

All input and output channels on the various Central IO modules are all connected on the 24 terminal screws divided across the two terminal blocks provided on each I/O terminal base.


Connect at least one RET terminal on each Central IO module terminal base to a common signal/earth ground rail in the enclosure using 1.3mm 2 (16 AWG) or larger wire. This connection is important for reducing damage to the I/O bus system from a miswired power connection (24 VAC or larger) to the I/O field wiring.


After the initial connection of field wiring to the terminal bases, and after changes to the terminal base wiring, you should examine the voltages present on the terminal base screws with a DVM. Verify that voltages seen on the terminal base are within expected limits BEFORE plugging in the electronics modules. With AC/DC power supplies energized to the field devices, a voltage measurement between the terminal screws and earth ground will provide the opportunity to catch miswiring of the power supply or line voltages to the terminal bases which can be very damaging to the complete I/O bus after the modules are inserted.

  • Terminal Base Installation
  • Power Rating
  • PS-24V Power Supply Module
  • Automation Server Installation
  • AS-P and AS-P-NLS Installation
  • Module and MP Controller Status LEDs