Omron 3G3RX Series, Руководство пользователя

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4-160
4-4 Communication Function
4
Functions
CRC-16 Calculation Example
<Header and Trailer (Silent Interval)>
• Wait time from receiving the query from the master to the response by the Inverter.
• Be sure to provide 3.5 characters (24 bits) as the wait time. If the length does not reach 3.5
characters, the Inverter does not respond.
• The actual communication wait time is the total of the silent interval (3.5-character length) and
C078 (communication wait time) setting.
Message Configuration: Response
<Total Communication Time>
• The time from receiving query to the response by the Inverter is the total of the silent interval (3.5-
character length) and C078 (communication wait time) setting.
• If sending another query to the Inverter after receiving the response, be sure to provide the silent
interval length (3.5 characters) at the minimum.
<Normal Response>
• If the query is the loop-back function code (08h), the Inverter sends back a response of the same
content as the query.
• If the query is the function code to be written into the holding register or coil (05h, 06h, 0Fh, 10h),
the Inverter sends back the query as it is in response.
• If the query is the function code to be read from the holding register or coil (01h, 03h), the Inverter
makes the slave address and function code the same as the query and attaches the read data to
the query.
CRC-16
calculation
CRC
*1
= FFFFh
CRC
*1
Hi Lo
CRC register (2 bytes)
Target data
Exists
All target data
completed
Interchange the Hi and Lo
bytes of CRC
*1
Completed
CRC
*1
= CRC
*1
XOR target data
8-bit shift
Completed
Bits left
Shift CRC
*1
= CRC
*1
by 1 bit to
the right
0
1
Overflow bit
after shift
CRC
*1
= CRC
*1
XOR A001h
Shift by 1 byte against target data