Fuji Electric FRENIC-AQUA series User Manual page 68

4.1 Messages
4.1.1 Message formats
The polling/selecting system is used to transmit and receive messages. The inverter always
waits for selecting (write requests) or polling (read requests) from a host such as a personal
computer or PLC.
When the inverter in the standby status receives a request frame from the host addressed to
itself (local station) and considers the request frame to have been normally received, the
inverter executes the transaction in response to the request, and sends back an
acknowledgement (ACK) frame (or response and data in the case of polling). If the inverter
judges that the receiving failed, it returns negative acknowledgment (NAK) frame. In the case of
broadcast (all station batch selecting), the inverter does not send back response.
(Each frame is described in Section 4.1.2 "Transmission frames.")
Polling
Host
Inverter
Selecting
Host
Inverter
Broadcast
Host
Inverter
Broadcast (all station batch selecting)
A frame with the station address set to 99 is treated by all inverters as broadcast.
By using broadcast, operation or frequency commands can be simultaneously assigned to all
inverters.
In broadcast communications, only selecting of S01, S05, S06, S13, S14, S19, S31 to S33, and
S90 to S93 in the standard frame, and commands (W, E, a, e, f, and m) in the optional frame
are valid.
Request frame
Read request
Request frame
Write request + data
Request frame
Write request + data
4-1
4.1 Messages
Response + data
Response frame
Response
Response frame