Page 7 - Industrial Technology EXTRA 28th September 2020

levels of current drawn. This can initiate
specific remedial functions such as a clean
cycle on a pump application or even stop the
system in the event of particular conditions to
prevent additional costly damage within the
application.
Most recently, Mitsubishi Electric has
extended the diagnostics capabilities of VSDs
by integrating Smart Condition Monitoring
(SCM) technology, introducing the concept of
drive-based condition monitoring. The pre- given tasks. Pump control is an example in VSDs
configured, plug-and-play solution includes the from many manufacturers but what about even
SmartCheck vibration sensor from Mitsubishi more specialised tasks? These can be addressed
Electric’s e-F@ctory Alliance partner Schaeffler and through dedicated parameters or the addition of
utilises the VSDs integrated PLC to provide a specific hardware within the VSD.
complete drive-based solution for preventative Examples include sensorless torque control to
maintenance. regulate tension in a winding application, such as in
Within the VSD, operating temperature and a paper mill, where the VSD adjusts the torque
vibration feedback from the SmartCheck sensor is command value according to the inertia of the paper
combined with the monitoring of a full range of roll. This function also supports taper tension and
other external parameters. These include speed, inertia compensation. Traditionally all of this would
voltage and current information, with detailed be regulated by external tension controllers, with
diagnostics highlighted on an integrated GOT feedback to the PLC and a control signal sent to the
display. With this added diagnostics capability, it is VSD but with sensorless torque control built in, the
now possible to not only monitor the health of the VSD can handle it all with just the setting of a few
VSD but also the health of the asset. internal parameters.
All of this extended functionality is given For crane and hoist applications, where there is
additional power when network capability within a tendency for the load to act like a pendulum,
the VSD is considered. With a host of protocols Mitsubishi Electric has developed a set of
supported without the need for option cards and configurable algorithms that can be used to lessen
indeed the ability to communicate over two different or even eliminate this effect. A further function can
protocols simultaneously, there is a seamless flow of prevent crabbing on travel cranes by providing
data from the drive. This encompasses plant level synchronisation of the driven wheels.
communication, via CC-Link for example, up to All of this extended functionality represents the
controller level, edge computing level or the higher here and now for VSDs, delivering enhanced
level enterprise over Ethernet. capability for some extremely challenging as well as
sophisticated applications. It takes the drive well
Special purpose drives beyond just speed and torque control and highlights
While many VSDs are general purpose products how the modern VSD can truly form the basis of a
suited to a wide range of applications, there is a highly sophisticated automation platform.
growing trend to incorporate features specific to gb3a.mitsubishielectric.com

September 2020 • INDUSTRIAL TECHNOLOGY EXTRA • p7