Mitsubishi Electric FR-A700 Series, Техническое руководство

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461
PARAMETER
2
P
ARAM
ETE
R
(3) Message format
1) Query
The master sends a message to the slave (=
inverter) at the specified address.
2) Normal Response
After receiving the query from the master, the
slave executes the requested function and returns
the corresponding normal response to the master.
3) Error Response
If an invalid function code, address or data is
received, the slave returns it to the master.
When a response description is returned, the
error code indicating that the request from the
master cannot be executed is added.
No response is returned for the hardware-
detected error, frame error and CRC check error.
4) Broadcast
By specifying address 0, the master can send a
message to all slaves. All slaves that received the
message from the master execute the requested
function. In this communication, the slaves do not
return a response to the master.
The slave executes the function independently of
the inverter station number setting [
Pr. 117, 331
]
during broadcast communication.
(4) Message frame (protocol)
z Communication method
Basically, the master sends a query message
(question) and the slave returns a response message
(response). When communication is normal, Device
Address and Function Code are copied, and when
communication is abnormal (function code or data
code is illegal), bit 7 (= 80h) of Function Code is
turned on and the error code is set to Data Bytes.
The message frame consists of the four message
fields as shown above.
By adding the no-data time (T1: Start, End) of 3.5
characters to the beginning and end of the message
data, the slave recognizes it as one message.
z Protocol details
The four message fields will be explained below.
Data check time
Item Check Time
Various monitors, run command
set frequency (RAM) 12ms
20ms
Parameter read/write, frequency setting
(EEPROM) 30ms
50ms
Parameter clear/all clear
5s
Reset command No answer
Query
communication
Query Message
Query Message
Response Message
Inverter (slave)
Inverter (slave)
Programmable
controller (Master)
Broadcast
communication
Programmable
controller (Master)
No Response
Inverter response time
(Refer to the following
table for the data
check time)
Data absence time
(3.5 bytes or more)
A700 F700
E700 D700
A700 F700
E700 D700
Query message from Master
Device Address Device Address
Function Code Function Code
Eight-Bit
Data Bytes
Eight-Bit
Data Bytes
Error Check Error Check
Response message from slave
Start
1)
ADDRESS
2)
FUNCTION
3)
DATA
4) CRC
CHECK
End
T1 8bit 8bit
n 8bit
L
8bit
H
8bit
T1