Yaskawa VS-616G5 Modbus Plus Communication Card - Manual (Page 37)

Special Modbus Plus Functions 7-5
Writing to the Global Frequency Reference Multiplier
In some applications, it will be necessary to change the frequency of multiple drives at the same
time. The global write function can easily be used to write a single value for frequency reference
to all of the drives connected on the MB+ network. In this way, all the selected drives can receive
the same frequency reference value at the same time.
System or process applications may require each drive to run at a different output frequency while
changing speed simultaneously with other drives. For systems that require this feature, the
Global Frequency Reference Multiplier can be used.
VS-616G5 Register F201h is the Global Frequency Reference Multiplier register. The power-up
default value of this register is ‘1.000’.
To make use of the Global Frequency Reference Multiplier, VS-616G5 register F200h must be
setup to enable global data.
When global data is properly initialized, the value written to VS-616G5 Register 002h (frequency
reference) will be multiplied by the value of VS-616G5 Register F201h (global frequency reference
multiplier) to produce the frequency reference value. This will allow each drive on the network to
scale the global frequency reference that it receives.
The diagram below shows a global frequency reference value of 30.00 Hz being written to 3
drives. Each drive has a different Global Frequency Reference Multiplier value.
An example of using the Global Frequency Reference Multiplier can be found in Chapter 9:
Example #6 (global frequency multiplier).
VS-616G5
node #1
VS-616G5
node #4
VS-616G5
node #2
Global Frequency
Reference
= 30.00 Hz
Global
Frequency
Reference
Multiplier
= 2.000
Global
Frequency
Reference
Multiplier
= 0.250
Global
Frequency
Reference
Multiplier
= 1.000
Calculated
Frequency
Reference
= 60.00 Hz
Calculated
Frequency
Reference
= 7.50 Hz
Calculated
Frequency
Reference
= 30.00 Hz