ENOTEC OXITEC 5000 Oxygen Analyzer Maintenance Guide

Gas path connection and flow rate setting

The instrument air version requires clean, dry, oil-free compressed air with an input pressure typically between 2-10 bar. The reference air continuous flow rate should be maintained at 30-40 l/h, and the test air should be maintained at 150-180 l/h during calibration. The maximum pressure of the test gas cylinder is 3 bar, and the commonly used test gas is a nitrogen mixture of 2.1% O ₂, with a flow rate of approximately 180 l/h (under 1.1 bar conditions). If using the pump version, with ambient air as the reference source, usually only the test air flow rate is adjusted.

In the gas path connection of the probe, use a blue tube for reference air and a green tube for testing gas. The bottom or back of the electronic unit is equipped with test air inlet/outlet and reference air inlet/outlet interfaces. The minimum bending radius of pneumatic cable FEP-0002 is 138 mm, with an installation temperature of -5 ° C to+50 ° C and an operating temperature of -40 ° C to+90 ° C. All air circuit joints should be correctly assembled using support sleeves, snap rings, and nuts to ensure no leakage.

Initial power on and display interface

After turning on the power, the system first displays a startup message, followed by prompts to select language, set date and time, enter TAG number, and optional ENOTEC REMOTE code. Afterwards, the probe enters the heating stage, and the display screen will show the current temperature, heating progress bar, and status. After heating is completed, enter measurement mode. After the first debugging, a two-point calibration should be performed 24 hours later.

The measurement interface usually displays TAG, O ₂ measurement value, current range, alarm indication, soft key menu, etc. The keyboard area includes three LEDs: Alarm, Maint., and Error. Alarm is orange, indicating a limit alarm; Maint. is orange, indicating maintenance mode; Error is red, indicating a system error. The system code defaults to 0000 at the factory. It is recommended to make changes after debugging and save them properly.

SYS-MENU and Key Parameters

SYS-MENU can view actual measurement values, including O ₂ value, mA output, sensor mV, reference air flow rate, probe temperature, heating power, thermocouple mV, terminal temperature, internal temperature, process pressure, sensor life, and Lambda. In the calibration results, the calibration date, method, offset, slope, test gas data, and response time can be viewed. Equipment operation data includes power on times, operating hours, and internal minimum/maximum temperature.

The O ₂ range can be freely configured, with a common range from 0-2% to 0-25%. The analog output can be set to 0-20 mA or 4-20 mA. In case of system error, the mA output can be set to 0-3.55 mA or 20.41-20.80 mA. The O ₂ limit alarm supports min/max and hysteresis settings; If the delay is 0.00%, it needs to be manually reset after triggering. The default test gas application time is 10 minutes, which can be adjusted within 5-30 minutes. If the sensor is not stable within the maximum time, it will prompt calibration failure. ACAL automatic calibration can be timed, triggered through digital input or "time+digital input". Two ACAL points need to be permanently connected to the test gas cylinder and kept open.

Key points of calibration operation

One point calibration is used to determine sensor offset, usually only test air is introduced. Two point calibration simultaneously determines offset and slope, requiring the introduction of test air and test gas. When manually calibrating, enter CAL-MENU and select either 1-point or 2-point calibration. The system will prompt to apply test air or test gas, displaying trends, flow rates, target values, and progress. During the calibration process, if the difference between the measured value and the test air concentration exceeds 3.00%, the system will prompt to return to the process. The calibration result can be displayed for up to 1 minute before resuming measurement.

The stability criterion is based on the final measurement value: if the new value exceeds the tolerance, the internal timer will reset and save the new value; If the timer is not reset, the signal is considered stable. Usually, the unit constant or slope is calculated using the final stable value after 2 minutes. The response time of mA output to changes in O ₂ sensor input is less than 200 ms.

Maintenance and replacement of vulnerable parts

The maintenance cycle depends on the flue gas conditions. Corrosive components such as SO ₂ HCl、 Continuous reducing atmosphere, dust, and solid particles can accelerate probe aging, filter clogging, and sensor drift. It is recommended to check the sensor every six months using test gas and test air; If the deviation is significant, perform two-point calibration; Visually inspect the probe and clean the filter at least annually.

When replacing filters, only ceramic, basalt, or sintered metal filters can be replaced. After removing the old filter, mix the supplied adhesive with water according to the instructions, apply it to the contact surface between the seat groove and the filter, push in and rotate the filter, evenly smooth and remove excess adhesive. The glue dries at room temperature for 24 hours. When replacing the probe, first turn off the power, open the junction box, loosen the flange bolts, use a new gasket, pay attention to the direction of the smoke, and adjust the V-shaped cover. Replacing the O ₂ sensor is usually only carried out when there is a leak or abnormal measurement value. The flange needs to be cleaned, new metal gaskets and four new screws need to be used, and the wires need to be connected before reinstalling and waiting for the working temperature. After 24 hours, perform two-point calibration.