Description
PR6426010-140+CON021 Emerson Eddy Current Sensor
PR6426010-140+CON021 is a dual channel differential expansion measurement component in the EPRO (now Emerson) MMS mechanical condition monitoring system in Germany. It consists of PR6426/010-140 differential expansion sensor and CON021 preamplifier, and is specifically designed for monitoring thermal expansion and differential expansion of large rotating machinery such as steam turbines.
PR6426010-140+CON021 Emerson Eddy Current Sensor
PR6426/010-140 is a dual channel eddy current differential expansion sensor. Channel 1 measures absolute expansion (thermal expansion of the cylinder relative to the base), while channel 2 measures relative expansion difference (expansion difference of the rotor relative to the cylinder). ‘010’ represents the sensor structure configuration, ‘140’ represents the range specification, and when used in conjunction with the CON021/916-240 preamplifier, the measurement range is plus or minus 12mm. The sensor adopts the non-contact eddy current principle, and the probe coil generates a high-frequency electromagnetic field. When the metal measured surface approaches, eddy current effect is generated, and the change in electromagnetic field intensity is proportional to the gap distance, thus achieving non-contact displacement measurement. The working temperature range of the sensor is negative 35 degrees Celsius to positive 380 degrees Celsius, suitable for zero to high speeds. It provides options for M10 or M18 threaded installation and rectangular flange installation. The cable can be armored or unarmored, and the end can be equipped with waterproof joints or bare wire.
CON021 is a supporting preamplifier and belongs to the MMS system signal conditioning module. Its core function is to convert the high-frequency oscillation signal generated by the sensor probe into a standard output signal consisting of a DC voltage proportional to the shaft displacement and an AC voltage superimposed. The input is compatible with the full range of eddy current sensors from PR6422 to PR6426, and the output provides two channels of 4 to 20mA current signal and 0 to 10V voltage signal. Each channel has open circuit, short circuit, and reverse protection. The power supply is redundant 24V DC input, diode isolated, with a power consumption of about 20W. In terms of preamplifier accuracy, when connected to PR6426, the linear error does not exceed plus or minus 1.5% of the full range, the temperature drift zero point is 200mV per 100K, the sensitivity temperature drift is less than 2% per 100K, the maximum time drift is 0.3%, and the power supply voltage error is less than 0.2% per volt. Equipped with RS232 interface for configuration and communication, the front panel has two green channel normal indicator lights and four red over limit indicator lights. Protection level IP20, compliant with Eex ib IIC T6/T4 explosion-proof standards. The rear connector is a 48 pin DIN 41642 standard terminal.
The component has been linearly calibrated with 42CrMo4 standard calibration material for the sensor and preamplifier before leaving the factory. During on-site installation, there is no need to recalibrate, only the air gap between the probe and the measured surface needs to be adjusted. In the same series, there are different range configurations such as PR6426/000-010 and PR6426/000-040, as well as preamplifiers with different ranges such as CON021/916-120, CON021/916-160, CON021/916-200, and CON021/916-240. Among them, 916-240 corresponds to a positive and negative 12mm range and is paired with PR6426/010-140 for use.
Typical applications include absolute expansion monitoring of steam turbine cylinders and relative differential expansion monitoring of rotors in scenarios such as thermal power plants and nuclear power plants. It is the front-end sensing element of the MMS6410 dual channel cylinder expansion measurement module and can also be directly connected to the MMS6000 series monitoring system to achieve differential expansion protection and trend analysis.
Summary in one sentence: PR6426010-140+CON021 is a dual channel differential expansion measurement component of EPRO, which synchronously measures the absolute expansion of the cylinder and the relative expansion difference of the rotor in a non-contact manner using eddy current. The range is plus or minus 12mm, and the preamplifier outputs standard signals of 4 to 20mA and 0 to 10V. It is a mature solution that balances accuracy and reliability in steam turbine thermal monitoring.
