Powtran PI500-S 004G1, Руководство пользователя

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Appendix II
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II -1-3 Protocol description
PI500-S -S series inverter communication protocol is a asynchronous serial master-slave
communication protocol, in the network, only one equipment(master) can build a protocol
(known as “Inquiry/Command”). Other equipment(slave) only can response the
"Inquiry/Command"of master by providing data or perform the corresponding action according
to the "Inquiry/Command"of master. Here, the master refers to a Personnel Computer(PC), an
industrial control device or a programmable logic controller (PLC), etc. and the slave refers to
PI500-S -S inverter. Master can communicate with individUal slave, also send broadcasting
information to all the lower slaves. For the single "Inquiry/Command"of master, slave will return
a signal(that is a response) to master; for the broadcasting information sent by master, slave does
not need to feedback a response to master.
Communication data structure PI500-S -S -Sseries inverter's Modbus protocol
communication data format is as follows: in RTU mode, messages are sent at a silent interval of
at least 3.5 characters. There are diverse character intervals under network baud rate,
which is easiest implemented. The first field transmitted is the device address.
The allowable characters for transmitting are hexadecimal 0 ... 9, A ... F. The networked
devices continuously monitor network bus, including during the silent intervals. When the first
field (the address field) is received, each device decodes it to find out if it is sent to their own.
Following the last transmitted character, a silent interval of at least 3.5 characters marks the end
of the message. A new message can begin after this silent interval.
The entire message frame must be transmitted as a continuous stream. If a silent interval of
more than 1.5 characters occurs before completion of the frame, the receiving device will flushes
the incomplete message and assumes that the next byte will be the address field of a new
message. Similarly, if a new message begins earlier than the interval of 3.5 characters following
a previous message, the receiving device will consider it as a continuation of the previous
message. This will result in an error, because the value in the final CRC field is not right.
RTU frame format:
Frame header START Time interval of 3.5characters
Slave address ADR Communication address: 1 to 247
Command code CMD
03: read slave parameters
；
06: write slave parameters
Data content DATA(N-1)
Data content: address of function code parameter,
numbers of function code parameter, value of function
code parameter, etc.
Data content DATA(N-2)
………………………
Data content DATA0
CRC CHK high-order
Detection Value: CRC value.
CRC CHK low-order
END
Time interval of 3.5characters
CMD (Command) and DATA (data word description)
Command code: 03H, reads N words (max.12 words), for example: for the inverter with
slave address 01, its start address F0.02 continuously reads two values.
Master command information
ADR 01H
CMD 03H
Start address high-order F0H
Start address low-order 02H
Number of registers high-order 00H
Number of registers low-order 02H
CRC CHK low-order
CRC CHK values are to be calculated
CRC CHK high-order
Slave responding information
When F9.05 is set to 0:
ADR 01H
CMD 03H