Systems integrator Clint
Johnson of Control Freaks, has
developed an all-Mitsubishi
Electric solution for a machine
that produces biscuit crumbs,
cereal and snack foods.

Getting a consistent mix was
difficult; the liquid needed to form
pellets tended to cause the entire
mix to clog. The system includes
two horizontal spiral blade mixers.

These are run backwards and
forwards at different speeds
to achieve a thorough mix.

Johnson says: “Each
product seems to require a
unique pattern of fast and slow,
forward and backwards. We have
stored those profiles as recipes on
a Mitsubishi FX3U PLC, which
controls a number of 15 kW E700
and D700 VSDs on the mixer axes
over an RS485 network.”
Feedback loops read the
current in the motors to
gauge the mix consistency.

Several discrete safety zones
were defined within the
machine and connected with
a control system that could
determine whether to stop a
single zone, several zones or
the whole machine. Mitsubishi
recommended a single WS
Safety Controller. This was
networked with the FX plus
an E1163 HMI using Ethernet.