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How can I control ATV31 via the Modbus communication channel?

To control the ATV31 via the Modbus communication channel, it is first necessary to configure the Modbus communication parameters
in the ATV31 COM- menu.

Parameter Add sets the modbus address

Parameter tbr sets the transmission speed as described below;
4.8 = 4800 bps
9.6 = 9600 bps
19.2 = 19200 bps

Parameter tFO sets the data format as described below;
8O1 = 8 data bits, odd parity, 1 stop bit
8E1 = 8 data bits, even parity, 1 stop bit
8n1 = 8 data bits, no parity, 1 stop bit
8n2 = 8 data bits, no parity, 2 stop bit

Please note that these settings are not stored until the ATV31 power supply is switched off and on again.

Next, configure the command and reference channels. The Command channel is the channel which provides the ATV31 with signals to start and stop, the Reference channel provides the motor speed reference. 

These two items can be separated in terms of how they are programmed in the CtL- Command menu, as shown in the following examples;

Example 1
Both the command and reference come from the Modbus communication channel. 

CtL Command menu => Function access level: LAC =  L3: Access to advanced functions and management of mixed control modes.
CtL Command menu => Reference 1 configuration: Fr1 = Mdb: Reference via Modbus.
CtL Command menu => Mixed mode: CHCF = SIM: Profile not separate. 

Example 2
The command channel is separate from the reference channel. The speed reference is sent via modbus, control can be via the terminals, display terminal, etc.

CtL Command menu => Function access level: LAC =  L3: Access to advanced functions and management of mixed control modes.
CtL Command menu => Reference 1 configuration: Fr1 = Mdb: Reference via Modbus.
CtL Command menu => Mixed mode: CHCF = SEP: Profile separate.
CtL Command menu => Cd1: Configuration of command channel is selected from the following choices; 

tEr: Command via terminals
LOC: Command via keypad (ATV31...A only)
LCC: Command via remote display terminal
CAn: Command via CANopen network

Example 3
The command channel is separate from the reference channel. Only the command is via Modbus:

CtL Command menu => Function access level: LAC =  L3: Access to advanced functions and management of mixed control modes.
CtL Command menu => Reference 1 configuration: Fr1 is selected from the following options;

AI1: Analog input AI1
AI2: Analog input AI2
AI3: Analog input AI3
AIP: Potentiometer (ATV31pppA only)
UPdt: +/- speed reference via logic inputs
UpdH: +/- speed reference via the keys on the ATV31 or ATV31...A keypad or the remote display terminal
LCC: Reference via remote display terminal
CAn: Reference via CANopen network
 
CtL Command menu => Mixed mode: CHCF = SEP: Profile separate.
CtL Command menu => Cd1: Configuration of command channel = Mdb Command via Modbus network 

This completes the configuration changes required within the Altivar 31 to implement modbus control. The controlling PLC will require appropriate programming to ensure that the correct sequence of instructions is sent to the ATV31 to achieve the required functionality. For further information, refer to the following manuals;

ATV31 Modbus manual, document reference VVED303091 EN
ATV31 Communication variables manual, document reference VVED303092 EN
 

FA27932  |  08-Mar-2014  | Networking
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