Sinee EM500 - Correct and Incorrect Data Frames; Data Frame Processing; Modbus Response Delay

EM500 Open-Loop Vector Control Inverter User Manual
415
Bit rate
(bps)
Start-end
interval T
interval
(t
modify
)
Abnormal
interval T
abnormal
(t
modify
)
Remarks
4800
8
4
Normal frame permits the idle point level
≤3ms; when an idle level≥8ms, it means
the end of a data frame.
9600
4
2
Normal frame permits the idle point level
≤1ms; when an idle level≥4ms, it means
the end of a data frame.
19200
2
1
Normal frame permits the idle point level
＜1ms; when an idle level≥2ms, it means
the end of a data frame.
Higher
1
1
An idle level of 1ms means the end of a
data frame.
Figure 12-3 Correct and Incorrect Data Frames
12.4.2Data Frame Processing
After receiving a data frame, the system should process it first to judge whether it is
a legal frame sent to inverter. Then, check whether the data is correct and perform
corresponding processing. If the received frame is illegal, it will not turn data; if the
received frame is legal but incorrect, it will turn corresponding abnormality information
frame.
Legal frame: meet address (inverter or broadcast) and length (not less than 3)
conditions
Correct frame: a correct frame is a legal frame, of which corresponding memory
address is corrected, memory content is as defined and can be processed for the time
being.
12.4.3Modbus Response Delay
Define the time interval from the receipt of a valid data frame
[7]
(data on RS-485