HoneywellControlEdge HC900 Controller Specifications 51-52-03-31, January 2022

Ethernet network interface to an Experion server is via 

the controller host Ethernet 100 Base-T port using 

Modbus/TCP protocol. Client Stations over Ethernet 

allow multiple user access to a ControlEdge HC900

network. Using the large selection of standard 

operating display templates in Experion saves 

development time. When further customization is 

needed, the full graphic display development 

environment of Experion may be used to fully animate 

your process supervisory displays. 

A batch reporting option is offered in Release 500 and 

430 which enables batch reports to be created using a 

standard template. User-entered lot data is supported 

and up to 50 parameters can be defined for batch 

logging. The file can be exported in .csv format using a 

lot number-encoded filename.

SpecView32 Supervisory Software – SpecView32 

software can be used as a supervisory interface for 

thermal-based applications, offering historical trending, 

batch reporting, recipe development involving setpoint 

programs and simplified graphics configuration. 

ControlEdge HC900 parameters are simply selected 

from categorized lists for placement on userconfigured displays or onto display objects.

Network connection is via the controller host Ethernet 

10/100Base-T port using Modbus/TCP protocol. A 

variety of Windows operating environments are 

supported.

OPC Server – Network communication access to 

ControlEdge HC900 controllers through third party PC 

interfaces is simplified with Honeywell’s Matrikon OPC 

server software program. This software supports the 

Modbus/TCP interface to either redundant or non-redundant 

ControlEdge HC900 controllers. In redundant applications, 

Matrikon OPC Server software supports dual Ethernet 

connections to both C75 CPUs. Communications to the 

controller is maintained during a single network failure 

and/or following the transfer of the Lead function from one 

CPU to another. Compatible OPC client programs can use 

the Ethernet connection to the ControlEdge HC900 via 

Honeywell’s OPC Server for remote supervision, data 

collection or other supervisory functions.

Capacity

The capacity of the ControlEdge HC900 system is 

determined by the type of CPU selected, the quantity 

of I/O racks, the quantity’s type of I/O modules, the 

update rate (scan rate) required, and CPU memory. In 

most applications, the CPU memory limit has a low 

probability of limiting capacity. 

How many I/O channels?

Number of I/O is limited only by physical space. 

Namely, the number of racks, the number of modules 

per rack, and the number of channels in the modules.

In general, 

Maximum I/O channels = (max. number of I/O racks) x

(max. number of modules in each rack) x

(max. number of channels per module)

Examples

Maximum C30 I/O = 1 rack x 12 modules x 32 

channels per module = 384 I/O channels

Maximum C50, C70, C75 I/O = 12 racks x 12 modules 

per rack x 32 channels per module = 4608 I/O channels.

Maximum C75 Redundant UIO = 6 Redundant racks 

(12 racks) x 12 modules per rack x 14 channels per 

module = 1008 I/O channels.

How many function blocks (loops, programmers, 

etc.)?

Fixed limits are not imposed on function block types. 

Your configuration can probably contain as many of 

each function block as needed. The limit is reached 

when either

a) Dynamic memory is full or

b) Maximum function block quantity is reached or

c) Configuration memory is full or

d) Over 65,535 block configuration parameters or 

block inputs used (but not Block Outputs).

These limits are explained below.

a) Dynamic Memory

The rule of thumb is: Max. number of function blocks =

Dynamic memory ÷ memory per function block

The smaller the function block, the more of them can fit 

in your configuration.

b) Quantity

Memory limitation is not for function blocks.

Complex blocks such as PID, Programmer, and 

Scheduler Sequencer use more memory than simpler 

blocks like On/Off, Device Control, Auto/Manual Bias. 

For example, several thousand Auto/Manual Bias 

blocks would fit in the C30’s memory if not for the quantity 

limit of 400. 

Conversely, about 300 Scheduler blocks will consume all 

the C30’s memory despite the higher quantity limit of 400.

Scan Time Consideration

Another consideration when configuring function blocks is 

scan time and the potential for CPU scan time to become 

insufficient for the application.

The scan time of a controller increases in fixed increments. 

As function blocks are added to a configuration, the time 

needed to execute the total configuration is recalculated. If 

additional time is needed, the scan time will be increased to 

the next increment in sequence. (See Specification section 

for scan time increments)

How many recipes in my pool?

Unlike with function blocks, there is no quantity limit to 

recipes. The only limiting factor to recipe pool size is 

available memory. Whatever memory is unused by the rest