One, two or four transitions may be counted at a maximum combined rate of 250 kHz and be scaled internally from -999,999 to +999,999. counts. The input circuitry which 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 current 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 by the transmitter as corresponding to an integral number of revolutions of the shaft encoder. It is used by the transmitter to correct for any cumulative pulse count errors. Special circuitry corrects for width of the zero index pulse. A built-in isolated 5V, 10V or 15V dc excitation supply is available to power shaft encoders and eliminate the need for an external power supply.
With the Extended main board, the transmitter can can also output an analog signal that tracks scaled rate. For example, the output can track the speed of a moving slab or RPM of a roller. The output update rate for position or rate is normally set to a maximum of 25/sec, as determined by a user-programmable gate time.
Modbus protocol operation is fully compliant with the Modbus Over Serial Line Specification V1.0 (2002) for 2-wire, half-duplex connection. This includes RTU or ASCII modes, addressing of up to 32 devices per RS485 line without a repeater, and up to 247 digital addresses. Modbus operation allows devices by different manufacturers to be connected in parallel and be addressed using the same protocol.Laurel’s Laurel ASCII protocol allows up to 31 Laureate devices to be addressed on the same RS485 data line. It is simpler than the Modbus protocol and is recommended when all devices are Laureates. It also allows use of Laurel’s datalogging software.
Transmitter programming is via the unit's three-terminal serial port using Laurel's PC-based Instrument Setup Software. This software can be downloaded from this website at no charge. The required transmitter-to-PC interface cable is available from Laurel (P/N CBL03). Laurel's serial output transmitters and meters can also be part of PC-based data logging systems using Laurel's Datalogging Software, which operates under the Laurel ASCII Protocol. A single software command switches between the Modbus and Laurel ASCII Protocols.
Options include dual solid state relays for local alarm or control and an isolated 4-20 mA or 10V (selectable) analog output, effectively providing a linearized analog transmitter output that tracks the reading that would be transmitted digitally. The analog output provides 12-bit (4096 step) resolution of the output span and is ultra-linear to within one bit. Its accuracy is ±0.05% of span for all signal types, except for AC rms, where accuracy is ±0.1%. Output isolation from signal and power grounds is provided by a separate on-board power supply, which can drive 20 mA into a 500 ohm load for 10V compliance. Output isolation eliminates problems caused by ground loops.
Laureate transmitters are housed in a 35 mm DIN rail case that is only 22.5 mm (0.89") thick. Signal connections are via detachable screw clamp plug connectors.
|Type||Differential or single-ended quadrature|
|Transitions Monitored||x1, x2 or x4|
|Max Pulse Rate||250 kHz at x1, 125 kHz at x2, 62.5 kHz at x4|
|Internal Counts||-999999 to +999999|
|Position Error||No error contributed by transmitter|
|Quadrature Position Mode|
|Zero Adjust||-999999 to +999999|
|Span Adjuste||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|
|Serial I/O (standard)|
|Signal levels||RS485 (default) or RS232 (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 RTU, Modbus ASCII, Laurel ASCII (selectable)|
|Devices on RS-485 Line||32 max without a repeater.|
|Modbus Addresses||247 max|
|Modbus Modes||RTU or ASCII, 2-wire.|
|Modbus Compliance||Modbus over Serial Line Specification V1.0 (2002).|
|Transducer Excitation Output (standard)|
|Jumper Selection 1||10V @ 60 mA, isolated to 50V from signal ground|
|Jumper Selection 2||5V @ 50 mA, isolated to 50V from signal ground|
|Jumper Selection 3||15V @ 60 mA, non-isolated|
|Dual Relay Output (optional)|
|Relay Type||Two solid state relays, SPST, normally open, Form A|
|Load rating||120 mA at 130 Vac or 170 Vdc, 28 ohms series resistance|
|Analog Output (optional)|
|Output Levels||0-20 mA, 4-20 mA or 0-10 Vdc (selectable)|
|Compliance, 4-20 mA||10V ( 0-500 ohm load )|
|Compliance, 0-10V||2 mA ( 5 kOhm load )|
|Output Resolution||12 bits (4,096 steps)|
|Output Accuracy||±0.05% of output span|
|Output Isolation||250V rms working, 2.3 kV rms per 1 minute test|
|Standard power||95-240V AC ±10% or 90-300V DC|
|Low power option||12-30V AC or 10-48V DC|
|Frequency||DC or 47-63 Hz|
|Power Isolation||250V rms working, 2.3 kV rms per 1 min test.|
|Case Dimensions||120 x 101 x 22.5 mm|
|Case Mounting||35 mm rail per DIN EN 50022|
|Electrical Connections||Detachable screw clamp plug connectors|
|Operating Temperature||0°C to 70°C|
|Storage Temperature||-40°C to 85°C|
|Relative Humidity||95% at 40°C, non-condensing|
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.