Technical FAQs

Ask a Question

How can I control an ATV61/71 via the Modbus communication channel?

Issue:
How can I control an ATV61/71 via the Modbus communication channel?

Product Line:
Altivar 61, Altivar 71

Environment:
All

Cause:
Programming

Resolution:
To control the ATV61/71 via the Modbus RTU communication channel, it is first necessary to configure the modbus communication parameters.

In the ATV61/71 Communications menu, go into MODBUS NETWORK submenu.

Parameter Add (Modbus Address) is adjustable between OFF to 247.
Parameter TBR (Modbus baud rate) is adjustable from 4.8-38400 bauds.
4.8K
9.6K
19.2K
38.4K

Parameter TFO (Modbus format) is adjustable from 8-odd-1, 8-even-1, 8-neutral-1, and 8-netural-2.
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

Parameter TTO is the modbus timeout value adjustable from .1 to 30 seconds.

Please note that these settings are not stored until the ATV61/71 power supply is switched off and on again.
Next, configure the command and reference channels. The Command channel is the channel which provides the ATV61/71 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 Command menu, as shown in the following examples;
Example 1
Both the command and reference come from the Modbus communication channel. 
CtL Command menu => Reference 1 configuration: Fr1 = Reference via Modbus.
CtL Command menu => 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 => Reference 1 configuration: Fr1 = Mdb: Reference via Modbus.
CtL Command menu => Mixed mode: profile SEP: Profile separate.
CtL Command menu => Cd1: Command channel 1:  Configuration of command channel is selected from the following;
Terminals, HMI, Modbus, Com card, Prog. card.

Example 3
The command channel is separate from the reference channel. Only the command is via Modbus:
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
AI4: Analog input AI4
LCC: HMI
NDB: Modbus
CAN: Canopen
NET: Com. card
APP: Prog card
P1: RP
PG: Encoder

 
CtL Command menu => Profile separate.
CtL Command menu => Cd1: Configuration of command channel = Mdb Command via Modbus network 
This completes the configuration changes required within the ATV61/71 to implement modbus control. The controlling PLC will require appropriate programming to ensure that the correct sequence of instructions is sent to the ATV61/71 to achieve the required functionality.

Profile as I/O profile allows the first bit in the command word register 8501 to be a run forward.
The rest of the bits of the command word is programmed as seen fit.  
For further information, refer to the following manuals;
 
Was this helpful?
What can we do to improve the information ?