Parameter Description
Parameters
82
Example 5.
Write P.195 into 500 (this parameter range is set between 0 and 400)
Step 1 to 2: Omitted (same as Step 1 and 2 of Example 3);
Step 3: The position machine requests the inverter to write 500 in P.195 in Format A:
ENQ
Inverter station
number
0
Reference
code
HDF
Waiting
time
Data
HC350
SUM
CHECK
CR
H05
H30 H30
H44 H46
H30
H43 H33 H35 H30
H46 H35
H0D
Step 4. After the inverter receives and processes the information, because the data exceed
the set range of P.195, the data range is incorrect. The inverter will reply the error to
the position machine in Format D:
NAK
Inverter station
number
0
Error code
H0C
CR
H15
H30 H30
H43
H0D
3. MODBUS communication protocol
1). Message format
●
MODBUS serial transmission can be divided into two types: ASCII (American Standard
Code for Information Interchange)and RTU (Remote Terminal Unit).
Query Msssage
PC
（
Master
）
INV
（
Slave
）
Single
Response Message
ASCII
：
CR
、
LF
RTU
：
wait times >= 10ms
Response time for INV
Query Messsage
PC
（
Master
）
INV
（
Slave
）
Broadcast
No Response
(1). Query
Position machine (main address) sends messages to the inverter of the assigned
address (from the address).
(2). Normal response
After receiving the query from the Master, the Slave will execute the requested function
and ask the Master to send the normal response.
(3). Error response
When receiving invalid function codes, address or data, the inverter will send the
response to the Master.
