Pulsers with inductive pick-up

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Pulser with inductive pick-up

The pulser is used for quantity metering in conjunction with electromechanical pulse counters as a transmitter with output signals for electronic data processing.

Using the pulser, quantity measurements from volumetric meters can be converted into electrical pulses for remote transmission. The pulser is used in conjunction with a pulse amplifier or a frequency-to-current converter.

Дизайн

Electronic design
High pulse frequency (≤ 3000 Hz)
Electronic output
- 170 mA, 24 V DC (delivering current) for electromechanical pulse counters
- 2 mA, 24 V DC (absorbing current) for electronic processing

Функции

Pulse valence with quantity measurements

Conversion of metered quantities into electrical pulses

Measuring system for remote metering and digital data processing

The metering shaft of the volumetric meter drives a pulse disk. The vanes of the pulse disk successively enter the air gap of an inductive pick-up, thus changing the coupling between two coils. This causes a change in resistance that is converted into a pulse by the subsequent pulse amplifier, which also powers the pick-up.

The pulser operates without contacts. No measurable force is exerted on the disk. This means that the system is free from feed-backs.

Depending on the design, 10 or 100 pulses are produced for each revolution of the drive. The pulse amplifier amplifies the incoming pulses. A timing circuit prevents a continuous output pulse.

The quantitative value associated with one pulse depends on the value per revolution of the drive (pulses per liter or gallon) or on the respective volume of the measuring chamber of the drive.

Pulsers with two inductive pick-ups are available for systems for custody transfer as PTB regulations currently specify a duplicated transmission system with pulse comparison.

Pulse valence with flow measurements

Conversion of metered quantities into electrical pulses

Measuring system for flow measurement

During flow measurements, the change in resistance is converted to pulses by SITRANS F RA110. Each pulse corresponds to a given quantity of metered liquid. The number of pulses per unit in time (the frequency) is a measure of the flow rate.

SITRANS F RA110 converts the incoming NAMUR signals into load-independent direct current.

The electric pulser is available for 10 or 100 pulses per revolution. The choice depends on the smallest flow rate still to be indicated.

Чертеж

Pulser with inductive pick-up, dimension in mm (inch)

Схема подключения

Pulser with inductive pick-up, connection diagram for clockwise rotation; pick-up l to terminals 3 and 4 for counter-clockwise rotation

Технические данные

Pulse amplifier
Slot initiator	Sensor SJ 3,5-N-K37
Power supply (from SITRANS F RA110)	8 V DC, R_i approx. 1 kΩ (DIN 19234) C_i = 40 nF; L_i = 160 µH
Change in current consumption on pulse	≤ 1 mA/ ≤ 3mA (DIN 19234)
Permissible line resistance between pick-up and amplifier	≤ 50 Ω (DIN 19234)
Number of pulses per revolution of the drive	10 or 100
Phase position of the channels of the double pick-up	180 ° : 180 ° ± 30 ° Electrically offset 90 ° ± 30 °
Duty factor	1 : 1 ± 17 %
Max. pulse frequency	3 000 Hz
Pulse valence	Dependent on value per revolution of the drive of the respective meter
Permissible ambient temp.	-25 ... +100 °C (-13 ... +212 °F)
Degree of protection	IP43 to EN 60529 with register
	P65 to EN 60529 with protective cover
	This pulser has the EC-Type Examination Certificate PTB 99 ATEX 2219X.
Mounting position	Any
Weight approx.	1.2 kg (2.65 lb)
Ex approval	IIG EEx ia IIC T6