Modbus Drive Operations; Communications Timing - Omron Q2A Series Technical Manual

Set DIP switch S2 to the ON position on the last drive of the Modbus communication network to enable the
termination resistor.
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Modbus Drive Operations

Drive parameters will apply to the settings when the drive is running during Modbus communications. This
section gives information about the available functions and their related parameters.
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Executable Functions
A PLC can do these operations with Modbus communications. Parameter settings (except H5-xx) do not have an
effect on the availability of these operations.
• Monitor the drive status and operate the drive
• Set and view parameters
• Reset a fault
• Multi-function input setting (The input command from Modbus communications and MFDI terminals (DI1 to
DI8) are linked by a logical OR operation.)
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Drive Control
Select the external command that sets the frequency references and motor run/stop with Modbus communications.
Use the following information to set the parameters as specified by the application.
Table 6.3 Required Parameter Settings for Drive Control from Modbus
LOCAL Control Selected
External reference 1
External reference 2
For more information about operation mode selection, refer to b1-01 [Freq. Ref. Sel. 1] and b1-02 [Run Comm.
Sel 1]. Refer to H1-xx: MFDI Function Select = 9 [Ext. Ref. 1/2 Selection] for more information about external
command.
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Communications Timing

This section gives information about message timing.
To prevent overrun of the slave side, the master cannot send a message to the same drive for a selected length of
time.
To prevent overrun of the master side, the slave cannot send a response message to the master for a selected length
of time.
SIEPYEUOQ2A01A AC Drive Q2A Technical Manual
Figure 6.4 Wiring Diagram for More than One Drive
Parameter
b1-01 [Freq. Ref. Sel. 1]
b1-02 [Run Comm. Sel 1]
b1-15 [Freq. Ref. Sel. 2]
b1-16 [Run Comm. Sel 2]
6.2 Modbus Communications
Setting Value
2 [Modbus]
2 [Modbus]
2 [Modbus]
2 [Modbus] 6
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