Modbus – IAI America ROBO Cylinder Series User Manual

Page 106

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5. Modbus RTU

98

Modbus

(4) Query sample

A sample query that reads the current speed monitor (from address 900A

H

) of a controller of axis

No. 0 is shown below.

z

Query (silent intervals are inserted before and after the query)

01 03 90 0A 00 02 C9 09

Field

RTU mode

8-bit data

Start

Silent interval

Slave address [H]

01

Function code [H]

03

Start address [H]

900A

Number of registers [H] 0002

Error check [H]

C909 (in accordance with

CRC calculation)

End

Silent interval

The response to the query is as follows.

z

Response (silent intervals are inserted before and after the response)

01 03 04 00 00 03 E4 FA 88

Field

RTU mode

8-bit data

Start

Silent interval

Slave address [H]

01

Function code [H]

03

Number of data bytes [H] 04 (4 bytes = 2 registers)

Data 1 [H]

00 00 03 E4

Error check [H]

FA88 (in accordance with CRC calculation)

End

Silent interval

The current speed is “000003E4” o Convert into decimal number o 996 (x 0.01 mm/sec)

The current speed monitor is 9.96 mm/sec.

Example 2) : When the current speed reading is “FFFFFF35” (moving in the direction opposite

to the example above) o

FFFFFFFF

H

– FFFFFF35

H

+ 1 (make sure to add 1) o

Convert into decimal number o 203 (x 0.01 mm/sec) o

The current speed is 2.03 mm/sec.

Note The data of the response example is simply an example and will vary depending on

various conditions.

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