Digital calibration of all thermocouple ranges is performed the factory, with calibration data stored in EEPROM on the signal conditioner board. This allows signal conditioner boards and ranges to be changed in the field with no need for recalibration. Cold junction compensation automatically corrects for temperature variations at the thermocouple reference junction at the transmitter. Open sensor indication is standard and may be set up to indicate either upscale or downscale.

Fast read rate at up to 50 or 60 conversions per second while integrating the signal over a full power line cycle is ideal for peak or valley capture and for real-time computer interface and control.

Standard features of Laureate transmitters include:

• 4-20 mA, 0-20 mA, 0-10V or -10V to +10V analog transmitter output, isolated, jumper-selectable and user scalable. All selections provide 16-bit (0.0015%) resolution of output span and 0.02% output accuracy of a reading from -99,999 to +99,999 counts that is also transmitted digitally. Output isolation from signal and power grounds eliminates potential ground loops.
• Serial communications output, RS232 or RS485 (half or full duplex), jumper selectable. Three protocols are user selectable: Modbus RTU, Modbus ASCII, or Laurel ASCII. Modbus operation is fully compliant with Modbus Over Serial Line Specification V1.0 (2002). The Laurel ASCII protocol is simpler than the Modbus protocol and is recommended when all devices are Laureates.
• Dual solid state relays, isolated, for alarm or control. Rated 120 mA at 140 Vac or 180 Vdc.
• Universal 85-264 Vac power. Low-voltage 10-48 Vdc or 12-32 Vac power is optional.

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).

Operation as a Fast ON/OFF Controller or Supervisory Monitor

With the optional dual solid state relay output option, which has a typical response time of only 17 ms, Laureate temperature meters and transmitters can serve as extremely fast and accurate ON/OFF controllers for closed-loop temperature control. They can also serve as supervisory process monitors and provide alarms or shutoffs when processes exceed normal limits.

Multiple setpoint operating modes are individually selectable for each relay, as explained in the dual-setpoint controller page. Relay duty cycles and chatter can be minimized with programmable hysteresis and time delays. A band deviation operating mode can be selected for each relay, where an alarm is generated whenever the reading is a selected number of counts above or below the setpoint. The relay modes have to be non-latching, since 4-20 mA temperature transmitters do not offer external reset.