Types of data, Write function – Yaskawa VS-616G5 Modbus Plus Communication Card User Manual
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6-2 Basic MSTR Functions
Types of Data
The MB+ network allows for reading and writing to a drive(s) internal data registers. VS-616G5 /
Modbus Plus communication uses 16-bit holding registers. The drive’s registers are divided into
four functional classifications.
1. Command Data:
These registers control the operation of the drive, and accept
read/write commands from a network master device.
2. Parameter Data:
These registers are used to configure the operation of the drive
(parameter groups Ax-xx, bx-xx, Cx-xx, dx-xx, Ex-xx, Fx-xx,
Hx-xx, Lx-xx, & ox-xx). They accept read/write commands from
a network master device. After writing to the parameter data
registers, an ‘ENTER’ command is required to store the data in
the drive’s non-volatile memory. At a minimum an ‘ACCEPT’
command must be issued to allow the drive to run after a
parameter change.
3. Monitor Data:
These registers are used to monitor the operation of the drive,
and may only be read by a network master device.
4. Special Data:
These are “special” Modbus Plus registers: ‘ENTER’ Command,
‘ACCEPT’ Command, Global Data, and Global Reference
Multiplier.
NOTE
A listing of all the Command, Parameter, Monitor, and Special Data Codes for VS-616G5 /
Modbus Plus communications can be found in Appendix A of this manual.
Write Function
An MSTR write function (operation code = 1) will write data to one slave device on the network.
When using a MB+ network, an MSTR write function can be used to send the following types of
data:
??
Command Data Registers
??
Parameter Data Registers
??
Special Data Registers
An MSTR write function may take multiple scans of the PLC ladder logic to complete. Examples
of writing drive registers can be found in Chapter 9: Example #1 (write run/stop and frequency
reference), Example #4 (write global run/stop and frequency reference), Example #5 (write
acceleration and deceleration), Example #6 (write global frequency reference multiplier), and
Example #8 (write drive parameters).