Mitsubishi Electric fr-e700 series, Инструкция по эксплуатации

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Parameter Communication operation and setting
FR-E700 SC EC/ENE 6 - 267
Outline
The Modbus® protocol is the communication protocol developed by Modicon for PLC.
The Modbus® protocol performs serial communication between the master and slave using the ded-
icated message frame. The dedicated message frame has the functions that can perform data read
and write. Using the functions, you can read and write the parameter values from the inverter, write
the input command of the inverter, and check the operating status. In this product, the inverter data
are classified in the holding register area (register addresses 40001 to 49999). By accessing the as-
signed holding register address, the master can communicate with the inverter which is a slave.
The data check time related to different functions is shown in the table below:
●
Query
The master sends a message to the slave (= inverter) at the specified address.
●
Normal Response
Response after receiving the query from the master, the slave executes the requested function
and returns the corresponding normal response to the master.
●
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.
●
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.
NOTE There are two different serial transmission modes: ASCII (American Standard Code for Information
Interchange) mode and RTU (Remote Terminal Unit) mode. This product supports only the RTU
mode in which two hexadecimal coded characters are transmitted in one byte (8 bits) data. Only
the communication protocol is defined by the Modbus® protocol, and the physical layer is not
stipulated.
I001227E
Fig. 6-132: Message format
Item Check Time
Various monitors, operation command, frequency setting (RAM) < 20 ms
Parameter read/write, frequency setting (E²PROM) < 50 ms
Parameter clear/all clear < 5 s
Reset command —
Tab. 6-88: Data check time
NOTE
The inverter executes the function independently of the inverter station number setting (Pr. 117)
during broadcast communication.
Query communication
Query Message
Response Message
PLC (Master)
Inverter
(slave)
Data absence time
(3.5 bytes or more)
Inverter response time
(Refer to the following table for the data check
time)
Broadcast communication
Query Message
No Response
PLC (Master)
Inverter
(slave)