beautypg.com

Ronan X11CA User Manual

Page 8

background image

Rev 2.0 : X11CA-IM MASTER MODULE

6

EXAMPLE:
The following example reads registers 40108-40110 from the slave device 17.

11

HEX

= 10001

BIN

=17

DEC

6B

HEX

=1101011

BIN

=107

DEC

Field Name

Example (Hex)

Slave Address

11

Function

03

Starting Address Hi

00

Starting Address L

6B

No. of Points Hi

00

No. of Points Lo

03

Error Check (LRC or CRC)

--

Table 4-2 Modbus Function 3 Example-Query


Response

The register data in the response message is packed as two bytes per register, with
the binary contents right justified within each byte. For each register, the first byte
contains the high order bits and the second contains the low order bits.

EXAMPLE:
The following example is a response to the query.

Field Name

Example (Hex)

Slave Address

11

Function

03

Byte Count

06

Data Hi (Register 40108)

02

Data Lo (Register 40108)

2B

Data Hi (Register 40109)

00

Data Lo (Register 40109)

00

Data Hi (Register 40110)

00

Data Lo (Register 40110)

64

Error Check (LRC or CRC)

--

Table 4-3 Modbus Function 3 Example-Response

The register 40108 contains two byte values of 02 2B

HEX

(=555

DEC).

The register 40109 contains 00 00

HEX

(=0

DEC).

The register 40110 contains 00 64

HEX

(=100

DEC).