application of proportional hydraulics
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APPLICATION OF PROPORTIONAL HYDRAULICS
The force of clamping machine used to clamp work-pieces of different kind of materials, needs a
number of pressure pre-sets which is selectable by pressing a number of pushbuttons.
The extension speed of a soft stamping machine has to be fast to reduce idle time. The stamping
effect on the surface of the material has to be soft.
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APPLICATION OF PROPORTIONAL HYDRAULICS
The table of a surface grinding machine has to move continuously under a grinding machine. The
table must decelerate when it is about to reach the end position, reversal gently and accelerate in
the opposite direction.
Different pressures are to be set on an injection moulding machine. The plastifying cylinder, fills
the mould with low filling pressure and completes the filling with a higher pressure. The cylinder
is to retract at low pressure.
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APPLICATION OF PROPORTIONAL HYDRAULICS
The hydraulic passenger lift must accelerate from stand still and decelerate to a stop to avoid
jumping and dropping effect to the passenger.
Honing machine require infinitely adjustable reverse points to suit the dept of the bore.
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PROPORTIONAL HYDRAULIC SYSTEM
Electrical and hydraulic signal flow
INPUT
Components that produces ELECTRICAL SIGNAL upon actuation
TYPES OF ELECTRICAL SIGNAL
1. Binary signal
- hanya boleh ON-OFF sahaja.
y ada signal 24v
y tiada signal ± hanging (voltage)
2. Analogue signal
y hanya boleh guna dalam PH
y Boleh hasilkan signal secara berterusan
A binary signal has only two values
VALUE ± O volt, VALUE ± 24 volt
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Components that produces binary signals are
1. Pushbutton switch
2. Roller limit switch
3. Pressure switch
4. Proximity sensor
Components that produces analogue signals are
1. Analogue pressure sensor
2. Analogue temperature sensor
3. Linera potentiometer
4. Proximity sensor
Process
Components that are used to create LATCHING and LOGIC FUNCTION
Processing components are relays and PLC.
A relay is an electrical component that consists of a coil and a set of contacts.
A PLC is a controller that can be programmed to provide logic functions.
Set point card
Specifies set point voltage for the amplifier