21 serial communications – Honeywell VRX180 User Manual

Page 175

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Programming Function Blocks and Features

Video Recorder – User Manual

161

4.21 Serial Communications

Serial Communications is an optional feature that lets the instrument exchange data with a host device
(a PC running Honeywell or other compatible software) on an RS422/485 data link. Using Modbus RTU
protocol, this link can be used to transfer configurations and data. Set up the link as follows.

Table 4-67 describes the Serial Communications prompts.

Table 4-67 Serial Communications Prompts

Prompt

Range/Selections

Definition

UNIT ADDRESS

1-254

Enter the unit’s address. Use a number once only so that each

address on the link is unique.

BAUD RATE

1200, 2400, 4800,
9600, 19200, 38400,
76800.

Enter the speed of data transfer. All equipment on the link must
be set to match the host setting.

DOWNLOAD

LOCKOUT

YES, NO

Set to YES to prevent configurations from being downloaded from
a PC with SCF software.

BYTE ORDER

FP_B : Big Endian

FP_BB : Big Endian
with Byte swap

FP_L : Little Endian

FP_LB : Little Endian
with Byte swap

This feature allows a user to select the byte order for a floating
point register.

Example for 25.38 :

Byte

order

Result

FP_B

FP_BB

FP_L

FP_LB

0123

1032

3210

2301

41CB0A3D

CB413D0A

3D0ACB41

0A3D41CB

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