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The Laureate quadrature transmitter accepts A & B quadrature encoder signals to provide an analog output that tracks position, length, angle, or rate. The A & B quadrature signals are 90° out of phase, and their phase relationship determines whether up counts (+) or down counts (-) are produced.
One, two or four quadrature transitions may be counted at a maximum combined rate of 250 kHz and be scaled internally to ±999,999 counts. The input circuitry may be jumpered for either single-ended input signals or for balanced line driver signals. Anti-jitter circuitry eliminates errors produced by vibration of the encoder. In the event of a power failure, the latest total may be stored in non-volatile memory and can be used as the starting point for counting when power resumes. Power fail or zero index capabilities are alternate meter setup choices.
A zero index pulse, if available, is interpreted as indicating a zero reference for an integral number of revolutions of a rotary shaft encoder or as the home position of a linear encoder. It is used by the meter for initializing and to correct for any cumulative pulse count errors. Special circuitry corrects for width of the zero index pulse.
Bidirectional Total or Rate
Unidirectional Total and Rate
If the counts are only for one direction, for example for extusions measured by an encoder wheel, only the encoder's "A" channel can be used and be output to an Extended Laureate totalizer transmitter. This model accommodates very high pulse rates up to 1 MHz, and unlike the quadrature transmitter, it can simultaneously track rate and total.
Standard features of Laureate LT transmitters include:
Easy Transmitter programming is via Laurel's Instrument Setup Software, which runs on a PC under MS Windows. This software can be downloaded from this website at no charge. The required transmitter-to-PC interface cable is available from Laurel (P/N CBL04).
| Quadrature Inputs | |
|---|---|
| Type | Differential or single-ended quadrature |
| Transitions Monitored | x1, x2 or x4 |
| Max Pulse Rate | 250 kpulses/sec at X1, 125 kpulses/sec at X2, 62.5 kpulses/sec at X4 |
| Internal Counts | -999999 to +999999 |
| Position Error | No error contributed by transmitter |
| Differential High Threshold | +200 mV |
| Differential Low Threshold | -200 mV |
| Differential Limits | -11V to +14V |
| Single-Ended High Voltage | 2.5V to 10V |
| Single-Ended Low Voltage | -1V to +1V |
| Input Resistance, Typ. | 17 kOhm |
| Quadrature Position Mode | |
| Zero Adjust | -999999 to +999999 |
| Span Adjust | 0 to ±999999 |
| Quadrature Rate Mode | |
| Conversion Technique | Inverse period |
| Output Update Rate | 30 ms + 0-2 signal periods |
| Gate time | Selectable 10 ms to 199.99 s |
| Time Before Zero Output | Selectable 10 ms to 199.99 s |
| Time Base Accuracy | Calibrated to ±2 ppm |
| Zero Adjust | -999999 to +999999 |
| Span Adjust | 0 to ±999999 |
| Analog Output (standard) | |
| Output Levels | 4-20 mA, 0-20 mA, 0-10 Vdc, -10 to +10Vdc (user selectable) |
| Compliance, 4-20 mA | 10V (0-500 ohm load) |
| Compliance, 0-10V | 2 mA (5 kOhm load) |
| Output Resolution | 16 bits (65,536 steps) |
| Output Accuracy | ±0.05% of output span |
| Output Update Rate | 25/sec max |
| Output Isolation | 250V rms working, 2.3 kV rms per 1 minute test |
| Serial Data Output (standard) | |
| Signal Types | RS232 or RS485 (half or full duplex), jumper selectable |
| Data Rates | 300, 600, 1200, 2400, 4800, 9600, 19200 baud |
| Output Isolation | 250V rms working, 2.3 kV rms per 1 min test |
| Serial Protocols | Modbus TCP, Modbus RTU, Modbus ASCII, Custom ASCII |
| Modbus Compliance | Modbus over Serial Line Specification V1.0 (2002) |
| RS232/RS485 Connector | Screw terminals for easy daisy chaining |
| Digital Addresses | 247 for Modbus, 31 for Custom ASCII |
| Dual Relay Output (standard) | |
| Relay Type | Two solid state relays, SPST, normally open, Form A |
| Load Rating | 120 mA at 140 Vac or 180 Vdc |
| Sensor Excitation Output (standard) | |
| Output Levels | 5V@100 mA, 10V@120 mA, 24V@50 mA (jumper selectable) |
| Output Isolation | 50V from signal ground |
| Power Input | |
| Standard Power | 85-264 Vac or 90-300 Vdc |
| Low Power Option | 10-48 Vdc or 12-32 Vac |
| Power Frequency | DC or 47-63 Hz |
| Power Isolation | 250V rms working, 2.3 kV rms per 1 min test |
| Power Consumption at 24V | 1.5W typical, 3W with max excitation output |
| Mechanical | |
| Dimensions | 129 x 104 x 22.5 mm case |
| Mounting | 35 mm rail per DIN EN 50022 |
| Electrical Connections | Plug-in screw-clamp connectors |
| Environmental | |
| Operating Temperature | 0°C to 55°C |
| Storage Temperature | -40°C to 85°C |
| Relative Humidity | 95% at 40°C, non-condensing |
| Cooling Required | Mount transmitters with ventilation holes at top and bottom. Leave 6 mm (1/4") between transmitters, or force air with a fan. |
| Using Quadrature for Cutting to Length | |
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Controlling the repetitive cutting of material to length is an excellent application of a Laureate quadrature transmitter or Laureate quadrature meter. The quadrature encoder shares the shaft of a sensing wheel, whose rotation corresponds to lineal displacement of material. The transmitter compares the displacement reading against setpoint information, and then uses its dual relays to first slow down and then cut the material. |
| Using Quadrature for X-Y Positioning | |
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Accurate X-Y position or rate can be obtained from two shaft encoders, which convert linear position to quadrature signals as a shaft turns. In addition to serving as a transmitter, each Laureate transmitter or meter can use its optional dual relay setpoint capability for closed loop control. |
| Using Quadrature to Monitor a Drilling Operation | |
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Quadrature can be used to track position and vertical drilling speed of the bit in an oil drilling operation. A shaft encoder is rotated by a cable that moves with the drilling shaft. In this application, the same encoder signal is applied to a Laureate quadrature transmitter for position, and to a second quadrature transmitter for rate. Both transmitters can send a 4-20 mA signal to a control room and be alarmed. In this application, quadrature provides much higher immunity to noise and jitter than a magnetic pickup. |
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