Bespoke Instrumentation - Case Studies
Water In Oil Detector
JK Controls have designed, developed and built
a device for detecting the interface between water and oil.
A way of detecting if
water is present beneath the waste oil and fat collected for
recycling and processing into bio-diesel was required. Our solution involved
building a device with an LED array that illuminates as the probe passes
through oil and encounters a layer of water. The device is made of
materials that resist corrosion and boiling water and can cope with a
harsh operating environment. A pair of handles are fitted for ease
of use and to aid insertion through hard fats. The detector is
battery operated, with the batteries housed in a separate compartment to
the electronics. It will switch off automatically after 20 minutes
to conserve battery life. There are internal adjustments for
changing the sensitivity (Span) of the detector and also for setting the
zero of the LED array. Click
HERE for a PDF with
further information and images.
Aircraft Wing Brake Test Rig
JK Controls have designed, developed and built
bespoke instrumentation and controls for a test stand for a prototype aerolon
Remote camera controls
The aerolon drive shaft is held by an
electrically operated brake when not required to rotate. The brake has to
bring the shaft to a halt within 40mS of being de-energised. For testing
purposes the shaft is rotated by a motor at up to 1500 rpm. The motor is
driven by a variable speed inverter at a preset speed. On de-energising
the motor, the shaft free-wheels for a few msecs and the speed is measured.
The brake is then de-energised and the shaft monitored until it ceases to
rotate. Timers automatically start and stop during the braking event.
This project required several custom designed
components where there were no suitable proprietary products available. As
the shaft stops within 40 msec. it only turns about one quarter of a turn
from running to stopped. Therefore the speed was measured using a very
fine resolution printed slotted wheel and a suitable optical detector.
Physical constraints prevented access to either end of the shaft, the slotted
disk was therefore custom made, together with the high speed optical detector by
JK Controls Ltd. Using fast hardware processing the shaft was determined
as stopped when the pulse repetition rate dropped below a threshold. The
timing and measurement logic was designed and built on to custom printed
circuits. During the braking period the brake torque is measured by a
strain gauge and the peak braking torque, in both directions, is stored.
Analogue hardwired circuits were built to sample-hold for peak torque and
initial speed stores. The stored values are displayed on suitably scaled
The sequence of running up the motor, priming the
data collection and timers, initiating the test and monitoring the results was
handled by a small PLC. Various safety interlocks are built in to prevent
operation under unsafe conditions. Great care was taken to minimise
sensitivity to, and radiation of, electro-magnetic interference.
Brake Test Rig
Peak Torque Detector
Typical console opened up
power plant company use many specialist techniques for plant inspections during
overhaul periods. One need was for an operator console to house the
controls and monitors. JK Controls Ltd built a pair of custom consoles
that could vary the lighting and monitor the temperatures of the cameras and
their inclination from normal within the plant. The horizontal shift of
one camera could also be altered remotely to adjust the stereoscopic imaging.
JK Controls have also built bespoke control consoles for video display,
recording and camera monitoring.
Cable wrapper speed analysis
A specialty cable manufacturing company required a
measurement of deceleration of cable insulation winding heads with a time
resolution of a few milliseconds. Access to the plant was extremely
restricted. JK Controls designed and manufactured signal conditioning
equipment and a small custom transducer to run on the surface of the winding
head. The measured speed was recorded on a high speed recorder which could
indicate any non-linearity in the deceleration and any over-run of the drive
Generator loading monitor
Power station operators have to supply power to the
National Grid within very tight margins. If they run below target they
suffer penalties, but if they supply above target they do not get paid for the
excess energy. To walk this tightrope during steady running is sometimes
difficult, but to follow the moving target load after synchronizing and whilst
raising load is much more difficult.
JK Controls have built a PC based monitoring
system that enables the operator to input the type of run up and the target load
and time. This will then draw the load trajectory on the screen with
tramlines to indicate the tolerance allowed. Once synchronized, the
generator load will be plotted on this screen in real time and the operator will
endeavour to drive the plant to maintain the generator output within the
Retrofit Solutions - Case Studies
Legacy Alarm System Renewal
A power station's ageing alarm system
had become obsolete due to the original manufacturer no longer being in
business. JK Controls provided a cost effective solution by analysing
the existing system and then designing and building new solid-state based
circuit boards to electrically emulate and be physically plug compatible with
Original obsolete Alarm card
New plug compatible Alarm card
Vector Meter Retrofit
JK Controls have recently
designed and built modern electronic Vector Meters to replace the original
obsolete mechanical instruments in a Scottish power station. The
Vector Meters can be setup using jumpers to take either 4 - 20 mA or 0 - 10
Volt input signals. The two input signals, mega Watts and mega VArs
are galvanically isolated and displayed on a TFT screen mounted within the
operators control desk.
Original obsolete mechanical Vector Meter.
Modern replacement electronic Vector Meter.
JK Controls replaced an
obsolete control system
for a power station's
generator/grid switchgear within a two day outage. This was achieved by
the manufacture of custom interfacing equipment which was plug compatible with
the original system I/O connectors, thereby providing considerable cost
benefits to the station in terms of downtime and future reliability.
Virtual Chart Recorders
Ageing and obsolete control room
recorders at a power station in Kent had become unreliable and expensive to
maintain. JK Controls designed and built a virtual recorder system based
upon PLC input equipment and three SCADA PC's driving twelve TFT liquid
crystal monitors. Each display emulated four multi-pen chart recorders
and was mounted in an add-on section of control desk designed by JK Controls,
which integrated with the operators original desk. The resulting
flexible data display system was provided at low cost compared to replacement
costs for the existing recorders.
Contact Information: e-mail to firstname.lastname@example.org,
or telephone +44 1732 522353
Address: JK Controls Ltd, The Barn, 65 High Street, East Malling, Kent, ME19
6AJ.. Reg. No.
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