SMAR fy303, Operation, Maintenance & Instruction Manual

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Operation
2.3
D/A
Receives the signal from the CPU and converts it to an analog voltage proportional the desired
position, used by the control.
Control
Controls the valve position according to the data received from the CPU and the Hall effect sensor
feedback.
A/D
Receives the signal from the Hall Sensor and converts it to a digital value proportional to the actual
valve position.
Hall Effect Sensor
Measures the position actual and feedback to the control and CPU.
Temperature Sensor
Measures the temperature of the transducer assembly.
Isolation
Its function is to isolate the fieldbus signal from the piezoelectric.
EEPROM
A non-volatile memory which stores configuration data as a backup.
Central Processing Unit (CPU), RAM, PROM and EEPROM
The CPU is the intelligent portion of the positioner, being responsible for the management and
operation of block execution, self-diagnostics and communication. The program is stored in PROM.
For temporary storage of data there is a RAM. The data in the RAM is lost if the power is switched
off, however the device also has a nonvolatile EEPROM where data that must be retained is stored.
Examples of such data are: calibration and valve configuration.
Communication Controller
A monitor line activity, modulates and demodulates communication signals and inserts and deletes
start and end delimiters.
Power Supply
The positioner circuit receives supply from a 9 to 32 Vdc power supply. Use of PS302 is
recommended.
Display Controller
Receives data from the CPU and drives the (LCD) Liquid Crystal Display.
Local Adjustment
Local adjustment is provided by means of two magnetic naturally actuated switches with no external
electric or mechanical contact, by using a magnetic screwdriver.
Piezo Flapper Nozzle
The unit flapper nozzle converts the movement of piezoelectric into a pneumatic signal to control
pressure in the pilot chamber.
Restriction
The restriction and the nozzle form a pressure-divided circuit. Air is supplied to the nozzle through a
restriction.
Spool
The spool ensures a quick valve positioning by providing a greater air flow than one provided by the
restriction.