Maintenance and troubleshooting of ENOTEC SILOTEC 8000 silo analyzer

After turning on the power, the system prompts to select language, set date and time, enter TAG number, ENOTEC Remote password (if enabled), and probe cable length. The cable length must be accurately inputted, as incorrect length can lead to measurement deviation and even damage to the COe sensor. Then enter the heating stage: the O2 sensor is heated first, and after reaching 800 ° C, the COe sensor begins to heat up. The display screen shows the current temperature, set temperature, heating power, and waiting information.

In measurement mode, the screen displays O2 and COe measurement values, active range, trend bar, and limit alarm indicators. Three LEDs respectively indicate alarm (orange), maintenance (orange), and error (red). The keyboard has four soft keys and numeric keys. The system code is set to 0000 at the factory, so there is no need to enter it to enter the menu. For safety reasons, modifications should be made and saved properly. If the code is lost, only trained service personnel can perform a system reset.

Calibration menu and automatic calibration

SILOTEC 8000 supports 1-point calibration and 2-point calibration, which can be performed separately for O2, COe, or both simultaneously. One point calibration uses test air (20.95% O2) to determine the offset. Two point calibration uses test air and test gas to determine offset and slope. Calibration can be manually initiated in CAL-MENU, or automatically calibrated with ACAL timing or remotely triggered.

ACAL settings are only visible when enabled. The calibration method can be either 1-point (test air only) or 2-point (test air+test gas). The startup methods include: time triggered, time+digital input, and digital input. The digital input requires a 12-24V DC control voltage to be applied to the "calibration release" terminal. If the control voltage still exists after calibration, the calibration will immediately restart.

Before calibration, it is necessary to confirm that the test air and test gas flow rates are correct. The test air flow rate should be 60-80 l/h, and the sample gas extraction flow rate should be 40-80 l/h. For systems with traffic monitoring, traffic can be viewed in System Checks. Testing gas recommendation: O2 sensor should use 2.1% O2 to balance N2; COe sensor should use the gas specified in the test certificate. Test gas flow rate of 40-80 l/h, maximum inlet pressure of 3 bar.

During the calibration process, the display screen shows trend charts, current measurement values, flow rates, and progress bars. If the sensor signal is unstable, it will report "sensor calibration failure". At this time, the 'test gas application time' can be extended, with a default of 10 minutes at the factory and an adjustable range of 5-30 minutes. The pre blowing time is used to flush the sensor before 2-point calibration and is turned off by default. The delay time is used to maintain the final measurement value after calibration and display the trend.

Sensor replacement and measurement pool maintenance

Before replacing the COe sensor, the COe measurement must be set to OFF through software. Otherwise, the new sensor may be immediately damaged. Step: Turn off the COe measurement, cut off the system power, disconnect the gas circuit and electrical connections of the measurement cell, remove the insulation layer of the measurement cell, loosen the COe sensor lock nut, remove the clamping ring, O-ring, and retaining ring in sequence, and take out the old sensor. Be aware that the sensor may experience high temperatures.

When preparing a new sensor, insert the clamping ring, O-ring, retaining ring, and locking nut, paying attention to the inclined surface facing the O-ring. Insert the new sensor and tighten the locking nut. The system needs to be tightened again after running for 2 hours. Reconnect terminals 11-14, power on, and enable COe measurement. The software will ask if the sensor needs to be replaced, and after confirmation, enter the test certificate parameters: COe RH0, Offset, Alpha, Beta, Gamma, Delta, SO2 correction value. The RH0 value must be correct, incorrect values will immediately damage the sensor. If there is an input error, immediately close and restart COe measurement.

When replacing the O2 sensor or probe tube, first remove the measuring cell, take out the inner core, remove the filter head and test gas distributor, loosen the flange screws of the measuring cell, and remove the old sensor. Clean the flange, install new sensors and gaskets, reinsert the inner core, and ensure even spring pressure. Perform 2-point calibration under process conditions 24 hours after installation.

When maintaining the measuring pool, pay attention to the hot surface. Disconnect the power supply, remove the insulation layer, loosen the fixing screws of the tank body, and take out the measuring tank. If the COe sensor is removed for a long time, the guide tube must be sealed with a locking rod and sealing kit to prevent false air from entering. The filter inspection is carried out according to the process cycle, checking the sealing and locking nut, with a torque of 250Nm. The blowback module can be automatically triggered when the extraction flow rate is lower than the alarm value, or it can be started during calibration or sensor inspection. If the flow rate remains low for about 5 seconds after blowback, the system enters an error state.