| PULSE RATE TO DC TRANSDUCER |
Datasheet (Adobe Acrobat Format)
Applications : frequency, flow and speed conversions
This transducer produces a D.C. current or voltage signal whose magnitude is proportional to the frequency of incoming pulses.
Inputs may be received from a wide range of sensors, and may be in the form of either a pulse train or a contact closure. Both 2 and 3 wire sensors can be accomodated.
The output signal response time and ripple content is largely determined by the input frequency. This output signal may be used to drive a number of remotely installed instruments.
The incoming pulse is transmitted through an optocoupler (1), whereafter its shape is altered (2) into a form more suitable for triggering the monostable (3). The monostable output is smoothed/averaged by an S-filter (4) into a D.C. signal with magnitude proportional to the incoming pulse frequency. The output amplifier (5) transforms this signal into either a load independent current or voltage signal.
The auxiliary supply is transformed in P.T.s (6) and (7), rectified and smoothed in regulators (8) and (9) and then used to power both sides of the opto-isolated circuit.
| 1. Input | |
| Input quantity: | Sensors producing pulses with peaks > 5V (standard) (other values available on request), and contact closure. |
| Pulse length: | Pulse length/width not important, rather the mark-to-space ratio and the magnitude of pulse. |
| Frequency range: | 0 to 10kHz (upper limit depends on sensor type) Window versions are available.. |
| 2. Output | |
| Characteristic: | A or B or C or D. |
| Output quantity: | Impressed current signal (voltage signal on request). |
| Standard values: | 1, 5, 20mA. |
| Maximum load: | 500 Ohm at 20mA (other values on request). |
| Maximum output voltage: | 12V D.C. |
| Maximum output current: | 2 x rated (typical). |
| Ripple/Output variation: | <0.5% for >25% of range, >0.5% for <25% of range. |
| Response time (10-90%): | <10 x minimum period of input. |
| Settling time (1% of final value): | <30 x minimum period of input. |
| 3. Auxiliary Power Supply | |
| Voltage: | 110V or 220V 50 Hz ±20% (other values on request). |
| Burden: | < 6.0 VA at rated load. |
| 4. Accuracy | |
| Error limit at rated conditions: | ±1% of range at 20°C. |
| Linearity error: | 0.5%. |
| Long term drift: | 0.5%. |
| Temperature shift: | 400ppm/°C. |
| Variation with auxiliary supply: | 0.05% for ±20% variation. |
| 5. Protection | |
| Impulse test between isolated sets of terminals: | 5 kV (0,5J; 1,2/50 wave) (IEC Standard) |
| Voltage withstand rating between isolated sets of terminals: | 4 kV, 50 Hz A.C. for 1 minute |
| 6. Physical Constraints | |
| Working temperature: | -10°C to 55°C. |
| Position: | Surface mounting in any position indoors. |
| 7. Enclosure | K540: |