Emerson Epro CON021/916-240+PR6426/010-140 Eddy Current Sensor Converter

System Overview

This measurement chain is a specialized, long-distance configuration of the MMS 6000/3000 series. It combines the CON021 converter with the PR6426 high-temperature probe. This specific set is calibrated for a 24-meter total system length, which is typically required in massive hydro-generators or large-scale steam turbine halls where the instrumentation cabinets are located at a significant distance from the machine bearings.

Component 1: CON021/916-240 Signal Converter

The CON021/916-240 is the driver/transmitter. The "916-240" suffix is the critical hardware identifier, indicating internal compensation for the impedance and capacitance of a 24-meter cable run.

• Model: CON021/916-240
• System Calibration: Exactly 24.0 meters (Total of probe cable + extension cable).
• Output Signal: Standardized analog voltage, typically 0 to -20 VDC.
• Function: Oscillator/Demodulator that maintains a stable electromagnetic field at the probe tip despite the long cable attenuation.
• Mounting: Shielded aluminum housing for DIN-rail mounting.

Component 2: PR6426/010-140 Displacement Sensor

The PR6426 is the "Heavy Duty" variant of the Epro displacement sensors, designed for high-pressure and high-temperature zones within the turbine casing.

• Model: PR6426/010-140
• Tip Diameter: 8 mm.
• Measuring Range: Approximately 2.0 mm (Nominal).
• Integral Cable (010): 1.0-meter integral cable length.
• Protection (140): Stainless steel flexible armored conduit with high-temperature insulation (FEP/PFA).
• Environmental Limits: Built to withstand temperatures up to 180°C and high-pressure oil environments.
  

Key Performance Characteristics

• Extended Reach: The 24-meter calibration (916-240) is among the longest standard configurations available, allowing for centralized monitoring in very large plants.
• Sensitivity: Typically calibrated to 8 V/mm (200 mV/mil) when matched with the 24m driver and a standard 42CrMo4 steel target.
• Linearity Window: Provides accurate displacement data between -2 VDC and -18 VDC of the output signal.
• "Sensor OK" Monitoring: The system continuously monitors the 24m loop; if the cable is cut or the probe is damaged, the voltage moves outside the "OK" window, alerting the DCS/PLC.