Month: January 2026

3.5 Engineering Card

The System 57 engineering card provides full maintenance and set up facilities for each

channel card. The front panel has a series of tactile feedback push buttons that allows

checks of the alarm levels and performance to be carried out for each channel. A real-time

‘on board’ clock provides calibration history and calibration overdue reminder functions. An

access key provides security protection.

The engineering card can be fitted with optional modules for extended system options.

3.5.1 Serial Communications Module

The serial communications module provides a gateway between the System 57 rack and a

remote device (DCS, PLC or SCADA package) to allow the continuous monitoring of each

channel’s operation and condition as well as allowing remote configuration of the system

operation. The module uses the industry standard MODBUS RTU protocol, RS485/422/232

standard. Custom designed SCADA graphics packages are also available.

3.5.2 RS232 Printer Driver Module

The printer driver module provides a serial output in the event of a gas alarm, fault or user

intervention. The output is RS232 ASCII event data, has selectable print criteria, provides

time and date stamping and is electrically isolated.

3.5.3 Master Alarm Update Module

The alarm update module provides a common alarm indication with new alarm event update.

It also provides 2 Outputs: 1 relay, 1 Darlington, with selectable operation: pulsed or

continuous and an alarm and common alarm reset input. It complies with ISA ‘M’, DIN 19

235. It can be used with the optional master alarm update panel.

3.6 Interface Cards

There are 9 versions of interface card available (5 for 5701 Gas, 2 for 5704 Gas and 2 for

5704 Fire Control Cards). The interface cards provide the link between the various fire or

gas detectors and the control cards. They provide detector interface, offer flexible relay

options, and allow an individual control card power option. A high integrity relay operation

version is also available. The terminals accept ≤ 2.5mm2 (14AWG) gauge cable.

3.7 Rack Assemblies

System 57 racking units provide mounting options for the system 57 control cards and

interface cards. The racks are available complete with a DC input card and an engineering

card. The racks are 3U high, with front or rear wiring options. Half and full 19″ versions are

available accommodating up to a maximum of 64 channels of gas detection or 60 channels

of fire detection in a single rack, or a combination of both.

3.8 Cabinet Assemblies

The System 57 cabinets provide a convenient and compact mounting of the rack assemblies

and PSUs. They are wall mounting and available in half and full 19″ versions. The cabinets

have an IP54/Nema 12 ingress protection rating, pre-formed bottom-entry knock-out gland

entries and an accessory mounting plate.

3.9 DC Input Card

The DC input card is connected directly to the engineering card and provides the connection

point for power supplied to the whole rack. The field wiring from the engineering card is also

on this card. It provides a common power supply wiring point, reverse polarity and short

circuit protection and multi-supply input capability.

6 Detector Installation

Cabinet outline dimensions

Always install the detectors in accordance with the Detector Operating Instructions. In

general, detectors for lighter than air gasses should be located at a high level and detectors

for heavier than air gasses should be located at a low level.

Do not install the detectors:

a. Where the normal air flow may be impeded.

b. In corners of rooms where static air pockets may exist.

c. Near sources of heat such as convector heaters.

Do install the detectors:

a. As close as possible to the potential source of gas to be detected in order to give the

maximum possible warning.

b. So that they are accessible for maintenance work.

05701-A-0329 by Honeywell | 3-Channel DPCO Relay Card Module

Manufacturer: Honeywell

Part Number: 05701-A-0329

Product Type: 3-Channel DPCO Relay Card Module

Product Overview

The Honeywell 05701-A-0329 is a rugged Triple DPCO (Double Pole Change Over) Relay Card engineered as part of the System 57 series.   It supports three independent relay channels, each equipped with dual Form C (SPDT) contacts, allowing versatile alarm, fault, inhibit, or general-purpose signaling.

Its 3U rack-mount form factor fits standard 19-inch enclosures, enabling straightforward integration into industrial safety and automation panels.   The LED status indicators on each channel provide clear real-time feedback, reducing troubleshooting time and ensuring operational transparency.

Built for harsh industrial environments, the 05701-A-0329 combines high durability, stable performance, and CE-certified compliance, making it ideal for gas detection platforms and other mission-critical systems.

Technical Specifications

Specification    Details

Manufacturer    Honeywell

Model Number    05701-A-0329

Type    Triple DPCO (Double Pole Change Over) Relay Card

Relay Channels    3 independent channels

Relay Contacts per Channel    2 × Form C (SPDT) relays

Relay Functions    Alarm, fault, inhibit, or general-purpose switching

Status Indicators    LED indicators for each channel

Form Factor    3U module for standard 19-inch rack mounting

Environmental Ratings    Resistant to vibration, dust, and temperature extremes

System Compatibility    Designed for Honeywell System 57 gas detection units

Compliance    CE marked;   meets Honeywell safety and EMC standards

Shipping Weight    2.5 kg

Rack Options

Racks are available in 4-slot, 8-slot, and 12-Slot versions. Racks are interchangeable between the Controller rack

and an I/O expansion rack, and all three versions shown in the following figure are available for either purpose.

8 and 12 slot I/O racks can be modified with additional slots for optional Reserve Power Supply and Power Status

Module.

Note: You can install redundant power on any 8 or 12 slot I/O rack.

Power Supply

The P01 Power Supply, shown in Figure 10. provides 5 Vdc and 24 Vdc to the backplane connectors in the local and

remote racks.  Power Supply is used in each Controller Rack, I/O expansion racks and for all rack versions (4-slot,

8-slot, and 12-Slot).

The lower capacity P02 power supply is available for reduced I/O applications and for Redundant Controller rack

power.

P24 power supply provides 5VDC and 24VDC to satisfy the power requirements of a single controller with I/O, a

Remote I/O rack or a Redundant C75 CPU.  The 60 watt capacity requires minimal de-rating of the available HC900

I/O modules.

A tool-secured door covers the voltage connections.  An internal non-replaceable fuse limits supply current under

certain fault conditions.

Each power supply includes an internal 5.0-amp fuse that

is not field-replaceable.  (An external fuse may be added

by the user. See page 25)

Items shown with key numbers:

1.  Voltage test points (P01model only)

2.  AC/DC Input terminal block

3.  Wiring label

4.  Grounding lug (Reference; lug is not part of Power

Supply; it is staked to bottom of Rack.)

The HC900-expansion I/O link is a private network and the switch used for the interconnection of the

HC900 Processor and Scanners must not be connected to any other LAN or WAN.  Likewise, no devices

other than the HC900 components should be connected to the I/O link Switch.  Failure to comply will

cause communication failures on the I/O link causing I/O modules to go in and out of their failsafe

settings.

Note: The HC900 is equipped with an Ethernet port as a standard feature (two Ethernet ports on the C70

& C75 CPU). These ports can function simultaneously as slave and master communications ports.

The dual Ethernet ports (C70 & C75 CPU’s) can be configured for redundant operation to a host.

If the host device does not have the inherent capability to recognize a network failover, the

Honeywell HWIOPC Server would be used to perform this functionality.

The dual Ethernet ports will not operate in a redundant configuration through a gateway to a

Host / server on another subnet. While both the E1 & E2 Ethernet can be configured with a default

Gateway address, only the E1 port will actually communicate across a gateway to another subnet

Hardware Components

This section contains general descriptions of each of the major components of the HC900 system.

For environmental specifications, refer to the section on Pre-Installation Planning.

HC900 Controller Rack

An HC900 Controller (“local rack”) is shown in the following figure. As indicated in this figure, the Controller Rack

includes:

1.  Rack, available in 4- 8-, or 12-slot versions

2.  Power Supply

3.  Controller Module

4.  Grounding bars (for I/O wiring; optional)

5.  Input/Output modules.

6.  I/O Terminal Blocks

HC900 Redundant Controller Rack

A HC900 Redundant Controller is shown in the following figure.

Rack

Redundancy Switch Module (RSM) . Interface between Lead/Reserve controllers.

Lead/Reserve controllers. Two C75 CPUs, designated “CPU-A” (left), “CPU-B” (right).

Two 900P01-xxxx or 900P02-xxxx Power Supplies

I/O Expansion Rack

I/O expansion (“remote”) racks, shown in Figure 8. are available to accommodate additional input/output modules,

and/or to enable location of I/O modules close to the process and remote from the controller. For C75/C75S, all I/O

is in a rack or racks separate from the controller rack.

Scanner type must match controller type. i.e. example S50S may only be used with C50S, or C70S.  S50S cannot be

used with a C50 or C70.

An I/O expansion rack includes:

1. Rack, available in 4- 8-, or 12-slot versions

2. Power Supply

3. Scanner 1 Module (S50/S50S) (shown) or Scanner 2 Module (S75/S75S)

4. Grounding bars (for I/O wiring; optional; required for

safety applications)

5. Input/Output modules

6. I/O Terminal Blocks

7. Power Status Module (PSM)

(req’d if using Reserve Power Supply)

8. Reserve Power Supply (optional). Available in 8- or 12

slot racks.

05701-A-0326  Honeywell System 57 Gas Detector Interface Card

Manufacturer: Honeywell

Part Number: 05701-A-0326

Product Type: System 57 Gas Detector Interface Card

Product Overview

The Honeywell 05701-A-0326 is a robust Field Interface Card engineered for Honeywell System 57 gas detection platforms.

It plays a vital role by connecting field-mounted detectors to the system’s controller, delivering amplified signals and reliable data transmission for continuous gas monitoring.

Its rugged construction and compact design allow smooth installation in challenging industrial environments where precise detection is critical.

Technical Specifications

Specification    Details

Model Number    05701-A-0326

Type    Pulse Preamplifier Controller / Field Interface Card

Input Voltage    9 – 32 VDC

Output Voltage    0 – 5 VDC

Functionality    Dedicated to receiving and amplifying signals from gas detectors

Relay Outputs    None – optimized for systems without relay requirements

Dimensions    16 cm × 10.9 cm × 4.3 cm

Weight    0.20 lbs (0.09 kg)

Compatibility    Fully integrates with Honeywell System 57 gas detection networks

Construction Features    Rugged enclosure designed for harsh industrial use

Ethernet 10/100 Base-T connection:

05701-A-0326

Port(s) configured to Auto Negotiate – default to half duplex

C30/C30S controller up to 5 PC hosts via Modbus/TCP protocol.   C50/C50S, C70/C70S and

C70R Legacy and C75/C75S (new model) support up to 10 PC hosts via Modbus/TCP protocol.

Peer-to Peer (UDP) communication with up to 32 other HC900 Controllers.

C70/C70S and C70R Legacy and C75/C75S (new model) have 2 Ethernet ports for connection to

up to 10 PC hosts.   They also support Modbus/TCP Initiator function over both ports and

automatically switch between ports to maintain Peer to Peer communications with other

C70/C70S or C70R/C75/C75S redundant CPUs.

05701-A-0326

Private Ethernet 100 base T connection to I/O expansion racks: (except C30 and C30S CPU)

Direct connection to each C70R Legacy and C75/C75S (new model) CPU.

Overview

This section provides a description of each of the major components that can be included in an HC900 Controller

physical configuration, and indicates some of the methods by which they can be combined.

Components

The Honeywell HC900 Process Controller includes a set of hardware modules that can be combined and configured

as required for a wide range of small to medium process control applications.

Some of the modules are required in all configurations.   Others are optional;  they are selected as appropriate to

provide optional functions and/or to “size” the system, either in initial planning, or in modifying and/or expanding

the system to meet changing requirements.

DI IOP Digital Input 32ch

The Honeywell 51304485-100 IOP and its compatible DI FTA can accommodates 32 contact inputs that share an isolated common return.

The 240 Vac Digital Input (DI) FTA is similar to the 120 Vac Digital Input FTA, except it accommodates a higher operating voltage, a lower sense current,

and the inputs of all 240 Vac DI FTA models are arranged in groups of eight channels, each with a common return for the group.

Digital Input IOP MU-PDIX02

CE-compliant, Non-Conformal Coated

Redundancy not supported

Input Channels: 32

Input Range:

w/24 Vdc FTA: 20-30 Vdc

w/120 Vac FTA: 90-132 Vac rms

w/240 Vac FTA: 180-264 Vac rms

Feature Summary

Hardware

51304485-100

Modular rack structure; components are ordered individually as needed

CPU with Ethernet and isolated RS485 communications

Easy to assemble, modify, and expand

C30 and C30S controllers provide local I/O connections while C50/C70 and C50S/C70S Controllers provide for

remote input/output rack connections over a private Ethernet-linked network

Parallel processing – a microprocessor in each I/O module performs signal processing, to preserve update rates

Power supplies – provide power to CPU rack and Scanner I/O racks

Redundancy

51304485-100

Redundant C75 CPU

Redundancy Switch Module (RSM) – required between redundant CPUs

Redundant Power Supply – provides redundant power to any CPU rack or Scanner2 I/O rack

Power Status Module (PSM) – required when using a second power supply in Scanner2 I/O rack

Communications

All CPUs (except where noted):

Serial Ports:

Legacy

Two serial ports, configurable for RS-232 or galvanically isolated RS-485 communications.

RS232 port can be used for link to PC for 900 Designer configuration tool (up to 50ft/12.7 Meters)

or via modem.  Also can be configured for Modbus RTU, master or slave.

RS 485 port used for 2 wire link to legacy operator interface (ELN protocol) or can be configured

for Modbus RTU, master or slave communications (up to 2000 Ft /600 Meters).

New Controllers

Two isolated RS 485 communications ports

USB to RS485 cable must be obtained to support link to PC for 900 Designer configuration tool

Can be configured for Modbus RTU, master or slave communications (up to 2000 Ft /600 Meters)

Process Manager (PM), Advanced Process Manager (APM) and High Performance Process Manager (HPM)

Common Set of IOPs and FTAs

All IOPs and FTAs are Usable by All (3) Controllers

The Honeywell TPS Process Manager I/O is made up of of Honeywell’s Process Manager (PM), Advanced Process Manager (APM) and High Performance Process Manager (HPM) system control and data acquisition devices for industrial process applications.

They represent a powerful combination of cost-effective Honeywell controllers which can be applied to solve a broad range of industrial process control problems.

The PM, APM, HPM, and EHPM offer highly flexible I/O (input/output) functions for both data monitoring and control.

One of the unique features of this family of controllers is its common set of Input/Output Processors (IOPs) and Field Termination Assemblies (FTAs).   All IOPs and FTAs are usable by all three controllers (with only minor exceptions).

I/O Processors, along with Field Termination Assemblies (FTAs), perform input and output scanning and processing on all field PM/APM/HPM/EHPM I/O.

A redundant I/O Link is standard for maximum security.

51304672-150

Optionally, High Level Analog Input, Smart Transmitter Interface, Analog Output, Digital Input and Digital Output processors can be redundant.

I/O processing is performed separately from control processing functions so that I/O scan rates are completely independent of I/O quantity, controller loading, processing, and alarming.

This partitioning of functions allows more efficient use of advanced Control Processor capability and provides for future I/O expansion.

ATTENTION

For the Legacy systems, it is specifically mentioned in the guide wherever applicable. The other

text is applicable to the new HC900 system. Modems are not qualified with the new HC900

system.

51304672-150

Checking HC900 Model Numbers for Compatibility

ATTENTION

Be sure to check your model numbers for compatibility before installation. For a HC900 system to

be fully compatible, all components must have matching model numbers.

Each component’s model number format is XXXXXXX–XXYY-ZZ. For example, HC900 CPU is 900C71R-0000

40. For redundant CPU systems, component model numbers ZZ numbers must match. For non-redundant CPU

systems, component model numbers YY numbers must match. See examples below.

Example of a compatible redundant system

Component

Model Number XXXXXXX-XXYY-ZZ

HC900 CPU

900C71R-0000-40

Scanner 2

900C73R-0000-40

HC Designer Software

900W01-0040-40

Manuals CD

900ME1-0040-40

Example of a compatible non-redundant system

Component

Model Number XXXXXX-XXYY-ZZ

HC900 CPU

900C51-0040-00

Scanner 1

900C53-0040-00

HC Designer Software

900W01-0040-40

Manuals CD

900ME1-0040-40