Honeywell UDC 3300 manual Introduction Communications group prompts, ComSTATE Com Addr ComADDR2

4.14 Communications Set Up Group

Introduction

Communications group prompts

This option allows the controller to be connected to a host computer via RS-422/485 or Modbus protocol.

The controller looks for messages from the computer at regular intervals. If these messages are not received within the configured shed time, the controller will SHED from the communications link and return to stand- alone operation. Depending on the protocol selected, the device address, parity, and baud rate are configurable. You can also set the SHED output mode and setpoint recall, and communication units.

Up to 99 addresses can be configured over this link. The number of units that can be configured depends on the protocol chosen:

•RS-422/485—15 drops maximum

•Modbus—15 drops (or 31 for shorter link length) maximum

Table 4-13 lists all the function prompts in the Communications Set Up group and their definitions.

Table 4-13 Communications Group Definitions

Lower Display

Prompt

ComSTATE

Com ADDR

ComADDR2

SHED ENAB

Upper Display

Range of Setting

or Selection

DISABL

MOD3K

MODBUS

RS422

1 to 99

1 to 99

DISABL

ENABLE

Parameter

Definition

COMMUNICATIONS SELECTION

DISABLE— Disables the communications option.

MB3K— Allows the UDC3300 to emulate the UDC3000A Modbus protocol.

MODBUS— Allows Modbus RTU communication prompts.

RS-422/485— Allows RS422/485 ASCII communication prompts.

COMMUNICATIONS STATION ADDRESS (LOOP 1)— This is a number that is assigned to a controller that is to be used with the communications option. This number will be its address.

COMMUNICATIONS STATION ADDRESS (LOOP 2)— This is a number that is assigned to a controller that is to be used with the communications option. This number will be its address. When ComSTATE = MODBUS, ComADDR2 = Com ADDR.

ATTENTION If RS-422/485 addresses on both loops are the same, then only Loop 1 will respond.

SHED ENABLE—Disables/enables shed functionaliy. Applies to Modbus protocol only.

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