Read Input Registers (Function Code 04) - ProSoft MVI56E-MNETCR User Manual

Modbus tcp/ip multi-client enhanced communications module for remote chassis
Table of Contents

Advertisement

Reference
User Manual
Adr Func
Data Start Reg Hi
11
03
00
Response
The addressed server responds with its address and the function code, followed
by the information field. The information field contains 1 byte describing the
quantity of data bytes to be returned. The contents of the registers requested
(DATA) are two bytes each, with the binary content right justified within each pair
of characters. The first byte includes the high order bits and the second, the low
order bits.
Because the server interface device is normally serviced at the end of the
controller's scan, the data will reflect the register content at the end of the scan.
Some servers will limit the quantity of register content provided each scan; thus
for large register quantities, multiple transmissions will be made using register
content from sequential scans.
In the example below, the registers 40108 to 40110 have the decimal contents
555, 0, and 100 respectively.
Adr
Func
ByteCnt
11
03
06

5.5.5 Read Input Registers (Function Code 04)

Query
Function code 04 obtains the contents of the controller's input registers at
addresses 3xxxx. These locations receive their values from devices connected to
the I/O structure and can only be referenced, not altered from within the
controller, The addressing allows up to 125 registers to be obtained at each
request; however, the specific server device may have restrictions that lower this
maximum quantity. The registers are numbered for zero (30001 = zero, 30002 =
one, and so on). Broadcast mode is not allowed.
The example below requests the contents of register 3009 in server number 11.
Adr Func Data Start Reg Hi Data Start Reg Lo
11
04
00
Page 128 of 161
Modbus TCP/IP Multi-Client Enhanced Communications Module for Remote Chassis
Data Start Reg Lo
Data #of Regs Hi Data #of Regs Lo
6B
00
Hi Data
Lo Data
Hi Data
02
2B
00
Data #of Regs Hi
08
00
MVI56E-MNETCR ♦ ControlLogix Platform
03
Lo Data
Hi Data
Lo Data
00
00
64
Data #of Regs Lo
01
Error Check Field
CRC
Error Check Field
CRC
Error Check Field
CRC
ProSoft Technology, Inc.

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the MVI56E-MNETCR and is the answer not in the manual?

Subscribe to Our Youtube Channel

Table of Contents