Azbil F4Q, Руководство пользователя

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4-5
Chapter 4. CPL Communication
Handling Precautions
•
The checksum of the instruction message cannot be omitted.
z CR and LF (Carriage Return / Line Feed)

Role : These indicate the end of a message.

Description : "CR" is (0DH), and "LF" is (0AH).
CR and LF must be used as a pair.
Handling Precautions
•
If any of the following problems is found in the data link layer, this device will
not respond.
•
The communication settings of the stations do not match (device address,
transmission speed, etc.)
•
The device address is set to "00."
•
STX, ETX, CR or LF are not in the right positions.
•
The device code is not "X."
•
The calculated checksum does not match the checksum in the message.
•
The message contains invalid characters.
•
The device address transmitted is different from the device address of the
target device.
•
In the data link layer, the same message (except for the checksum) as the
instruction message from the master station is used as the response message.
•
Use capital letters from "A" to "F" for the hexadecimal numbers used in the
device address and checksum.
•
If “1” (2 stop bits) is set for “Data format selection” of this device, messages from
the host device will be accepted regardless of whether they have 1 or 2 stop
bits.