Modbus – IAI America ROBO Cylinder Series User Manual

Page 246

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6. Modbus

ASCII

238

Modbus

(4) Query sample

An example of use is shown, where the current measurement on the load cell connected to

controller axis 0 is read.

Query: 01 03 90 0A 00 02 4C [CR] [LF]

Field

Fixed character strings in ASCII

mode

Converted ASCII

code data [H]

Start

‘:’

3A

Slave address [H]

‘0’, ‘1’

3031

Function code [H]

‘0’, ‘3’

3033

Start address [H]

‘9’, ‘0’, ‘1’, ‘E’

39393145

Number of registers [H] ‘0’, ‘0’, ‘0’, ‘2’

30303032

Error check [H]

‘4’, ‘C’ (in accordance with LRC

calculation)

3443

End

‘CR’, ‘LF’

0D0A

The response to the query is as follows.

Response: 01 03 04 00 00 03 E4 [CR] [LF]

Field

Fixed character strings in ASCII

mode

Converted ASCII

code data [H]

Start

‘:’

3A

Slave address [H]

‘0’, ‘1’

3031

Function code [H]

‘0’, ‘3’

3033

Number of data bytes [H] ‘0’, ‘4’ (2 bytes = 1 register)

3034

Data 1 [H]

‘0’, ‘0’, ‘0’, ‘0’

30303030

Data 2 [H]

‘0’, ‘3’, ‘E’, ‘4’

30334534

Error check [H]

‘1’, ‘1’ (in accordance with LRC

calculation)

3131

End

‘CR’, ‘LF’

0D0A

Example 1) The current measurement on the load cell is “000003E4, ” which is convert into a

decimal number, or 996 (x 0.01 N) Æ The current push force is 9.96 N.

Example 2) If the current measurement reading on the load cell is “FFFFFF35” (tensile state

(Note 2)

),

the formula FFFFFFFF

H

– FFFFFF35

H

+ 1 (1 must be added) applies. The result is

converted into decimal number, or 203 (x 0.01 N) Æ The current tensile force

(Note 2)

is

2.03 N.

Note 1 This is only one example of response. The specific response varies depending on each

situation.

Note 2 If a force is applied in the tensile direction, the load cell will break.

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