TECO 7200MA User Manual
7200M
A
RS-485 MODBUS Communication
Application Manual
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7200MA MODBUS Application Notes
1. Brief Introduction：
This manual describes the communication methods
between TECO frequency inverter 7200MA and host controllers(PC,PLC…).
2. Software Standard：
Using RS-485 Interface
c
MODBUS RTU mode protocol
d
e Communication Format
Transfer Speed：1200/2400/4800/9600 bps (Setting by parameter Sn-37)
Parity：no parity/even parity/odd parity (Setting by parameter Sn-38)
3. Wiring Terminal：
：(Setting by Inverter‘s parameter)
7200 MA
)
S(+
)
(
-
S
RS-485
Interface
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7200MA MODBUS Application Notes
4. Related parameters for MODBUS communication：
(1) Node address
Sn-36 =1~31 ------------------------- Inverter Node address (Default = 1)
(2) Transfer Speed (baud rate)
Sn-37 = 0------------------------------ 1200 Bps
= 1------------------------------ 2400 Bps (Default = 1)
= 2------------------------------ 4800 Bps
= 3------------------------------ 9600 Bps
(3) Data Parity
Sn-38 = 0------------------------------ No Parity (Default = 0)
= 1------------------------------ Even Parity
= 2------------------------------ Odd Parity
(4) Stopping method while RS485 Communication Fault
Sn-39 = 0------------------------------ Decelerating to stop by Bn-02
(Default = 0)
= 1------------------------------ Coasting to stop
= 2------------------------------ Decelerating to stop by Bn-04
= 3------------------------------ Continuous operation
(Can be stop by STOP
(5) Time-out Check
Cn-27 = 00.0 s ----------------------- Don‘t care
= 01.0 s ----------------------- Checked error (Default = 01.0 s)
Key)
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7200MA MODBUS Application Notes
5. Inverter connected with host controller：
(1) Operation procedure
Inverter power turn on，Set the related parameters
c
Connect inverter and host controller
d
Host controller sends communication message
e
(2) Communication status indication of inverter
We can set the Run/Stop command (Sn-04) or Frequency Reference
(Sn-05) by RS485. Inverter will display “Alarm RS-485” if it does not
receive any message from host controller after power on 5 seconds. This
display will disappear while inverter had received messages from host
controller.
We can set Time-out Check. Inverter will display “Alarm RS-485” if it does
not receive any message in Time-out (Cn-27).
Parameter Sn-39 will decide the “Alarm RS-485” display format.
Sn-39 = 0，Decelerate to stop by Bn-02 (“Alarm RS-485” light up)
= 1，Coasting to stop (“Alarm RS-485” light up)
= 2，Decelerate to stop by Bn-04 (“Alarm RS-485” light up)
= 3，Continuous operation (“Alarm RS-485” flash)
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7200MA MODBUS Application Notes
6. Description of MODBUS communication：
(1) In MODBUS RTU mode protocol，one message has 4 parts：
include Slave Address、Function Code、Data and CRC-16 Character.
The interval between two messages needs 3.5 characters transferring time.
T1 T2 T3 T4
Slave
Address
Function
Code
Data
Character
CRC-16
Character
T1 T2 T3 T4
T1~T4：3.5 characters transferring time at least
(2)Data bit format for MODBUS RTU mode
Even/Odd Parity start 1 2 3 4 5 6 7 8 parity stop
No Parity start 1 2 3 4 5 6 7 8 stop stop
(3) Slave Address
Parameter Sn-36 can set the node address of each inverter (1~31).
Every slave stand can receive the message sent from host controller.
Only the corresponding one returns the message to master.
IF the slave address of receiving message is 0, all slave stands will
execute this command but do not return the message to master.
This message can only use for Run/Stop, Fault Reset (Address 0000H)
and Frequency Reference (Address 0001H).
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7200MA MODBUS Application Notes
(4) Function Code
Code Function Remark
03H Read Data from Holding Register
08H Loop Test
10H Write Data to Holding Register slave address can be 0
(5) Data Character
Detail descriptions will be discuss later because it depends on different
Function Code.
(6) CRC-16 Character(16-bit binary value)
CRC-16 Generation Procedure：
Load a 16-bit register with 0xFFFF. Call this the CRC register.
c
Exclusive OR the first 8-bit byte of the message with the low order byte
d
of the 16-bit CRC
Shift the CRC register one bit to the right(toward the LSB), zero filling
e
the MSB. Extract and examine the LSB.
f If the LSB is 0, repeat Step
OR the CRC register with the polynomial value 0xA001.
g Repeat Step
When this is done, a complete 8-bit byte will have been processed.
Repeat Stepd〜g for the next 8-bit byte of the message. Continue
h
doing this until all bytes have been processed. The final result of the
CRC register is the CRC value.
When the CRC is placed into the message, its upper and lower bytes
i
e
register, putting the result in the CRC register.
(another shift). If the LSB is 1, Exclusive
e
and Step
until eight shifts have been performed.
f
must be swapped.
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7200MA MODBUS Application Notes
(7) Inverter return messages
Please refer to the “Message Format” in next page about inverter
c
returning messages for more detail descriptions.
It needs 5ms to return messages after inverter had received normal
d
message from host controller.
In next two cases, inverter does not return any message：
e
z There are any error detection in received data message (parity error,
framing error, overrun error or CRC-16 error).
z Slave Address character is different to parameter Sn-36 (Inverter
Slave No.).
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7200MA MODBUS Application Notes
7. Message Format：
7200MA supports 3 MODBUS Function Codes only.
Table1 Message Length
Function Code Description
Host Query Inverter Return
Byte
(Min.)
Byte
(Max.)
Byte
(Min.)
Byte
(Max.)
Data Read 03H
Loop Test 08H
Data Write 10H
Read Data from Holding Register
Loop Test
Write Data to Holding Register
88737
8888
11 41 8 8
(1) Read Holding Register Command(Item 8:Holding Register Tag List)
Host Query
Slave Address 01H
Function Code 03H
Head Address
Access Count
CRC-16
High Byte 00H
Low Byte 00H
High Byte 00H
Low Byte 01H
Low Byte 84H
High Byte 0AH
(*1)
Inverter Return(Normal)
Slave Address 01H
Function Code 03H
Data Byte Count 02H
High Byte 00H
Data Value
Low Byte 00H
Low Byte B8H
CRC-16
High Byte 44H
Inverter Return(Error Detected)
Slave Address 01H
80H+Function Code 83H
Error Code 03H
Low Byte
CRC-16
High Byte
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*1 Host controller can read 16 registers
at most in each transferring message.
01H
31H
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7200MA MODBUS Application Notes
(2) Loop Test Command(Test inverter communication status)
Host Query
Slave Address 01H
Function Code 08H
Test Code
Tes t Data
CRC-16
Inverter Return(Error Detected)
Slave Address 01H
80H+Function Code 88H
Error Code 01H
CRC-16
High Byte 00H
Low Byte 00H
High Byte AAH
Low Byte 55H
Low Byte 5EH
High Byte 94H
Low Byte
High Byte
87H
C0H
(*1)
Inverter Return(Normal)
Slave Address 01H
Function Code 08H
Test Code
Tes t Data
CRC-16
*1 Test Data can be any random value.
High Byte 00H
Low Byte 00H
High Byte AAH
Low Byte 55H
Low Byte 5EH
High Byte 94H
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