TC10EM
P. 8 / 43
EM-9581-B Rev.1
5-2-55, Minamitsumori, Nishinari-ku, Osaka 557-0063 JAPAN
Phone: +81(6)6659-8201 Fax: +81(6)6659-8510 E-mail: [email protected]
MODBUS COMMUNICATION
This device conforms with Modbus-RTU protocol (MODBUS APPLICATION PROTOCOL V1.1a / Modbus over Serial Line
Specification & Implementation Guide V1.0).
The following communication parameters are selectable.
COMM. PROPERTY
SELECTION
Node address
1 to 247
Baud rate
4800 bps
9600 bps
19200 bps
38400 bps (*)
57600 bps
Parity bit
None
Odd (*)
Even
Stop bit
1 bit (*)
2 bits
(*) Factory setting
When appropriately set, the host PC connected via RS-485 can read measurands from and write configurations (setting) to the device.
All registers are assigned to Holding Registers, can be read out using Read Holding Registers command. If reading an ad
-
dress with no assigned register is attempted, ‘0’ is given.
Write Multiple Registers command is used to write registers. If writing an address with no assigned register is attempted,
‘Exception’ is given.
FUNCTION CODE
COMMAND
RECOMMENDED TIME OUT VALUE
03
Read Holding Registers
0.5 seconds
04
Read Input Registers
0.5 seconds
06
Preset Single Register
2 seconds
16
Write Multiple Registers
2 seconds
These commands enable reading measurands and writing configurations.
Registers are represented in 16-bit integers. All registers are in the form of integer unless specifically given in the explana-
tions.
CAUTION : DO NOT apply new setting via Modbus and the front control buttons at once.
It is recommended to wait for a time period indicated under ‘recommended time out value’ in the above table to receive a
response for a command. If no response is received for these time periods, take appropriate error processing such as retrying.
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READING EXAMPLE
To read the MV value in the table below.
ADDRESS
PARAMETER
UNIT
5
Loop 1, Heating MV (control output)
0.01%
If 7510 is read, the register value is converted into actual engineering unit value by the following equation:
7510
×
0.01 = 75.10%
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WRITING EXAMPLE
To write 40.0 at the SP value in the table below.
ADDRESS
PARAMETER
RANGE
DEFAULT
1153
Loop 1, SP (setpoint)
-3200.0 to +3200.0
(decimal by input 1 decimal setting)
25.0
With the decimal setting ‘1’, write in ‘400’ for ‘400.’
With the decimal setting ‘2,’ write in ‘4000’ for ‘40.00.’
With the setting ‘3,’ ‘40000’ cannot be written as the maximum range is limited up to 32000.
