Honeywell Digital Output, 24VDC (32 channel)900H32-0101
Table 1 – Descriptions of Major Components (Figure 4)
Key No. Component
Name
Description Source
1 Controller
(Local) Rack
Includes: Rack, Power Supply, Controller Module, and
I/O modules
Honeywell
2 I/O Expansion
Rack
(C50/C70 CPU
only)
(Optional) Includes: Rack, Power Supply, Scanner
Module, and I/O modules
Honeywell
3 Control Station 900 Control Station operator interface communicates
via Ethernet or galvanically isolated RS-485 serial link
Honeywell
4 PC
Configuration
Tool (Serial
connection
option)
For legacy system- The PC configuration tool
connects from the RS-232 serial port of the
Controller Module to a serial port on the PC
For new system – The PC Configuration tool
connects from the galvanically isolated RS-485 port
of the Controller Module using an external
Honeywell qualified RS-485 to USB converter.
PC is from third-party
supplier. Configuration
software is from
Honeywell. RS-485 to
USB converter is a third
party device available
from Honeywell.
5 HMI (Human Machine
Interface)
(Optional) PC link to Ethernet network, which may
include other HMIs, other HC900 Controllers, and
other networks (including Internet).
Typically includes HMI operating software.
May also include Designer Software (configuration tool
and utility software).
PC is from third-party
supplier. HMI software is
available from Honeywell
(Experion HS or
SpecView32) or from
third-party supplier.
6 Qualified un managed
Ethernet
100Base-T
Switch
Enables connection of the private Ethernet 100Base-T
port on a Controller Module to the Scanner modules
on 2, 3, or 11 I/O Expansion racks. (C50/C70 CPU
only) (If a single I/O expansion rack is connected
directly to a Controller Module, the Switch is not
required.)
Qualified third party
devices available from
Honeywell
6a Ethernet
10/100Base-T
Switch or
Router/Firewall
Enables inter-connection of several 10/100Base-T
Ethernet devices in an Ethernet network. Devices
include other HC900 Controllers, HMIs, and can also
include routers, servers, and other devices in wider
networks.
Third-party suppliers.
7 Ethernet CAT5 shielded cable Connects I/O expansion racks
(C50/C70 CPU only) to controllers
and/or to 10/100baseT Ethernet
switches. 10’or 20’ (3.04 or 6.08m)
Third-party suppliers or
Honeywell
Fiber Optics Cable Connects I/O expansion racks
(C50/C70 CPU only) to controllers
with fiber switch.
8 Ethernet CAT5
shielded cable
Connects devices in Ethernet Open Connectivity
network to 900 Control Stations and PC SCADA
applications.
Third-party suppliers or
Honeywell

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.
Table 2 – Descriptions of Major Redundancy Components
Key No. Component
Name
Description Source
1 Controller
(Local) Rack
Includes: Rack, 2 Power Supplies, 2 C75
Controllers, 1 Redundancy Switch Module (RSM)
Honeywell
2 I/O Expansion
Rack
Includes: 1 Scanner 2 module, 1 Power Supply, and
up to 4, 8, or 12 I/O modules. Optional second
Power Supply and Power Status Module (PSM) on
8- and 12-slot I/O racks.
Honeywell
3 Control Station 900 Control Station operator interface
communicates via Ethernet or RS-485 serial link
Honeywell
4 PC
Configuration
Tool (Serial
Interface
option)
For legacy system- The PC configuration tool
connects from the RS-232 serial port of the
Controller Module to a serial port on the PC
For new system – The PC Configuration tool
connects from the galvanically isolated RS-485
port of the Controller Module using an external
Honeywell qualified RS-485 to USB converter.
PC is from third-party
supplier. Configuration
software is from
Honeywell. RS-485 to
USB converter is a third
party device available
from Honeywell.
5 HMI (HumanMachine
Interface)
(Optional) PC link to Ethernet network, which may
include other HMIs, other HC900 Controllers, and
other networks (including Internet).
Typically includes HMI operating software.
May also include Designer Software (configuration
tool and utility software).
PC is from third-party
supplier.
HMI software is
available from
Honeywell (Experion
HS or SpecView32) or
from third-party
supplier.
6 Qualifies unmanaged
Ethernet
100Base-T
Switch
Required if using 2 or more I/O Expansion racks.
Provides connection of the I/O Ethernet 100Base-T
port on a Controller Module to the Scanner
modules. Switch not required for connection to a
single I/O rack.
Qualified third party
devices available from
Honeywell
6a Ethernet
10/100Base-T
Switch or
Router/Firewall
Enables inter-connection of several 10/100Base-T
Ethernet devices in an Ethernet network. Devices
include other HC900 Controllers, HMIs, and can
also include routers, servers, and other devices in
wider networks. Use of a properly configured firewall
provides a more robust network limiting exposure to
uncontrolled network traffic.
Honeywell or third-party
suppliers.
7 Ethernet CAT5
shielded cable
Connects I/O expansion racks to controllers and/or
to 10/100baseT Ethernet switches. It also connects
to 900 Control Stations and PC SCADA software
applications.
Third-party suppliers or
Honeywell
9 RS-232 For legacy system, Null modem cable, up to 50’
(15.24m) (PC modem cable if used with Modems.)
For new systems, RS-485 to USB converter,
connects galvanically isolated RS-485 port to USB
port.
Third-party suppliers or
Honeywell