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