Drive Operations By Memobus/Modbus; Communications Timing - YASKAWA CIPR-CR70A Series Technical Manual

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Drive Operations by MEMOBUS/Modbus

The drive parameters apply to the settings even if the drive is run during MEMOBUS/Modbus communications.
This section describes the types of usable functions and their related parameters.
Executable Function
A PLC can perform the following operations with MEMOBUS/Modbus communications at any time regardless of
parameter settings (except for H5-xx).
• Observe the drive status and operate the drive from a PLC
• Set and view parameters
• Fault Reset Procedure
• Multi-function input setting (The input command from MEMOBUS/Modbus communications and MFDI
terminals (S1 to S10) are linked by a logical OR operation.)
Drive Control
Select the external command for setting the frequency references and the motor run/stop using MEMOBUS/
Modbus communications, and set the parameters according to the application using the following table.
Table 5.2 Required Parameter Setting for Drive Control from MEMOBUS/Modbus
LOCAL Control Selected
External reference 1
External reference 2
For more information about operation mode selection, refer to b1-01 [Frequency Reference Selection 1] and b1-02
[Run Command Selection 1]. Refer to H1-xx = 2 [MFDI Function Selection = External Reference 1/2 Selection]
for more information about external command.
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Communications Timing

To prevent overrun of the slave side, the master cannot send a message to the same drive for a certain amount of
time. Similarly, to prevent overrun of the master side, the slave cannot send a response message to the master for a
certain amount of time. This section explains the message send/receive timing.
Command Message from Master to Slave
To prevent data loss and overrun, after the master receives a message from the slave, the master cannot send the
same type of command message to the same slave for a certain amount of time. The minimum wait time differs
depending on the type of message. Check by referencing the following table.
Command type
• Operation commands (Run command, stop command)
1 • I/O settings
• Reading the motor and parameter setting values
2 Parameter writing
3 Writing of modified data with the Enter command
*1 If the drive receives a message within the minimum wait time, it executes command type 1 and sends a response message. If the
drive receives command type 2 and command type 3 messages within the minimum wait time, a communications error is generated
or the drive disregards the command it received.
YASKAWA ELECTRIC SIEP C710617 19A YASKAWA AC Drive CR700 Technical Manual
No.
b1-01 Frequency Reference Selection 1
b1-02
b1-15 Frequency Reference Selection 2
b1-16
Table 5.3 Minimum Wait Time until Message Transmitted
Example
Figure 5.5 Minimum Wait Time Until Transmit
5 Network Communications
Name
Run Command Selection 1
Run Command Selection 2
Setting Value
2 [Memobus/Modbus
Communications]
2 [Memobus/Modbus
Communications]
2 [Memobus/Modbus
Communications]
2 [Memobus/Modbus
Communications]
Minimum Wait Time
5 ms
*1
50 ms
*1
3 to 5 s
*1
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