Vigilantplant TDLS8000, Руководство пользователя

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<11. Modbus>
11-2
IM 11Y01D01-01EN
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Unit ID
Don’t care for Modbus/TCP. Slave devices simply return the received value.
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Function
The supported function numbers are listed in the following table.
Function no. Function Type Max. number of data points per transaction
1 Read coils Bit 2000 points
2 Read the input relays Bit 2000 points
3 Read hold registers Word 125 points
4 Read the input registers Word 125 points
5 Write to a single coil Bit 1 point
6 Write to a single hold register Word 1 point
16 Write to hold registers Word 123 points
43 Read device information ASCII string (*1)
*1: The following parameters, which are basic device ID parameters (in the basic category) are read by function 43.
ID Object name Meaning Value
0x00 VenderName Vendor name "YOKOGAWA"
0x01 ProductCode Product code "TDLS8000"
0x02 MajorMinorRevision Revision number
"[Device Revision]-[Software Revision]"
Example: "01-1.01.01"
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Data
There are two types of data: “coil/relay” in unit of bits and “register” in unit of 16 bits. Data
attributes and data addresses are shown in the following table.
Type Attribute Modbus name Address (*1) Application
Bit W Coil 0XXXX Instruction
R Input relay 1XXXX Status
Register R Input register 3XXXX Measured value
W Hold register 4XXXX Valve control, temperature/pressure input
*1: XXXX: 0001 to 9999
11.1.2 Slave Response
Function and subsequent content of response messages vary depending on whether there are
errors in instruction messages.
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Normal response
In the case of writing to a single coil or single hold register, the slave device returns the same
message as the instruction message. In the case of a read function, the read data is added to the
function in the response message. If an address in which no data is assigned is read, zero, not
an error, is returned as the read data.
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Error response
If there is an error in the instruction message, the slave device returns an error response without
executing the instruction. In an error response, the slave device returns the value obtained by
adding 128 to the instruction function as the error function. Therefore, the master device can
check the function in the response message to determine whether an instruction has been
accepted normally. If the master device determines an error has occurred, it can find out the
details by checking the error code.
The message structure from the function and beyond in an error response is as follows.
Error function (instruction fu 128)
Error code
3rd Edition: Jun. 10, 2016-00