Toho Electronics TTM-00BW, Руководство по эксплуатации

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6.5 Explanation about RTU Codes
■ The following codes from (a) Slave Address, (b) Function Code, up to (h) Error Code will be expressed
in 8-bit
binary:
a) Slave Address
It is an address of the device that will be communicated by the upper computer (this product).
The address in the response message from this product indicates the source of the response message.
b) Function Code
Enter the code 03H or 10H.
03H: If the data is to be read from this product
10H: If the data is to be written or saved into this product
c) Register Address
It specifies the position of data to be read or written with two bytes.
See "9. List of Identifiers (Codes)" for the address of each command.
Data will be retained in the holding register.
d) Number of Registers
It specifies the number of registers that write. Since the number of registers of this product
is fixed to 2, set it to "0002H."
e) CRC-16
It is an error checking code for the detection of the possible error in the message. It sends CRC-16
(Cyclic Redundancy Code).
Generating polynomial of CRC-16 that is used in this product is X16 + X15 + X2 + 1.
See "6.7 Sample Computation of CRC-16" for the computation method of CRC-16.
If it is to be attached at the end of the message as an error code, attach the lower byte of CRC
before the upper byte.
f) Number of Bytes
It specifies the number of registers that read and write x 2. Since the number of registers of
this product is 2 (fixed), set "04H."
g) Data Section
It specifies the data to be written into the register. Data is 4 bytes (fixed).
Data without decimal point will be written.
Example: In case of numerical data
Contents of Communication HEX Data
Proportional Band (P) = 1. 0% 0000000AH
PV = 200.0℃ 000007D0H
SV = - 10.00℃ FFFFFC18H
Example: ASCII code will be written in case of the character data (□ means space)
Contents of Communication HEX Data
Priority Screen 0- 1 = □INP 20494E50H
Priority Screen 0- 2 = □MV1 204D5631H
Priority Screen 0- 3 = □□P1 20205031H