Sanken SVCO6, Инструкция по эксплуатации, Страница: 281 / 326

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7
7-4 Serial Communication Function
7-4-6 Modbus-RTU Communication
The followings are descriptions of Modbus-RTU communication.
⑪
Message transmission and receive timings between inverter and computer
The transmission and receive timings of RTU message are as follows:
PC—inverter Inverter—PC
Response mode——————————————————————————————————
Command signal Response signal
T1 T2
PC—inverter Inverter—PC
Broadcast mode—————————————————————————————————
Command signal No response
T1: Data receive complete time
The maximum time for judging 1-frame data complete by message receive cycle is the time needed to transmit
3.5-bit data with current baud rate. Therefore, the response signal must be within the time of T1.
T2: Communication response time (F4004)
By changing the communication time, the response interval sent by inverter can also be changed.
The response mode is a normal or error response sent by inverter to the command from the PC.
No response is sent in broadcast mode.
〈
Communication timeout function
〉
In Modbus communication, the setting of function code F4101: Modbus communication timeout can be used to set
the response timeout during communication.
When exceeding the time period set by F4101, the inverter will act according to the setting of function code F4102:
Modbus communication timeout actions.
F4102=0 Status keeping
F4102=1 Alarm stop (GAL3 alarm)
⑫
Message format
The message format is as follows. The RTU format is consisted with data in hexadecimal.
Variable length