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Configuration Parameter Definitions
Modbus Communications Set Up Group
Release M
DR4500A Classic Series Circular Chart Recorder With or Without Control Product Manual
111
April 2017
4.12 Modbus Communications Set Up Group
Introduction
This option allows the DR4500A to be connected to a host computer via the Modbus protocol. Up to 99
addresses and a maximum of 15 units can be configured over this link.
REFERENCE
Refer to Documents
51-52-25-66
and
51-52-25-69
for a complete description of the RS485
Modbus Communications Option.
Communications group prompts
Table 4-12 lists all the function prompts in the Modbus Communications set up group and their functions.
Table 4-12 Modbus communications group definitions
Lower Display
Prompt
Upper Display
Range of Setting or Selection
Parameter Definition
ComSTATE
DISABL
MODBUS
DISABL
—Disables the communications option.
MODBUS
—Allows Modbus communication prompts.
Com ADDR
1 to 99
COMMUNICATIONS STATION ADDRESS
— This is a
number that is assigned to the recorder that is to be
used with the communications option.
BAUD
300
600
1200
2400
4800
9600
19200
38400
BAUD RATE
is the transmission speed in bits per
second.
300 Baud
600 Baud
1200 Baud
2400 Baud
4800 Baud
9600 Baud
19200 Baud
38400 Baud
XMT DLAY
NONE
10MSEC
20MSEC
30MSEC
40MSEC
50MSEC
TRANSMIT DELAY
—This is the approximate time
delay between receipt of Modbus request message and
start of response message (in addition to message
processing time).
DBL BYTE
FP B
FP BB
FP L
FP LB
DOUBLE REGISTER BYTE ORDER
—The transmitted
or received order of the 4 bytes comprising an IEEE
floating point value. The default order is EXP, MH, MM,
ML, or 0123 for reference.
0123
(Big Endian)
1032
(Big Endian, Byte Swapped)
3210
(Little Endian)
2301
(Little Endian, Byte Swapped)