1. Debugging Steps for E+H Dissolved Oxygen Transmitter COM223/COM253

1. Operation Key Function Description

Before debugging, please familiarize yourself with the operation key functions of the transmitter. The definitions of each key are as follows:

  • CAL key: Calibration key, activates calibration mode and enters the calibration menu.
  • + key: Numeric increase key; - key: Numeric decrease key.
  • E key: Confirm key, used to confirm a selection or input.
  • REL1 key: Manual relay operation key; REL2 key: Relay manual/automatic switching key.

2. Probe Inspection and Calibration

Probe calibration is a key step to ensure measurement accuracy. Please operate according to the following process:

  1. Install the membrane cap filled with electrolyte on the probe and expose it to air. Avoid direct sunlight, and the ambient temperature should preferably be controlled at 20°C to 25°C.
  2. Connect the secondary meter, press the CAL key, and enter password 22.
  3. Select air calibration and press the E key to confirm. At this time, the displayed value will begin to decrease from 600 until it reaches zero.
  4. If no fault code appears, calibration is complete.

After calibration is completed, check whether the displayed values are normal:

  • Altitude display value: should be between 6.00 to 11.20 mg/L or 85 to 157%SAT.
  • Salinity display value: should be around 9.20 to 9.30 mg/L or 102%SAT.

3. Range Setting Steps

Range setting includes unit selection and output current configuration. The specific steps are as follows:

  1. Unit setting: On the main interface, press the E key, code0 is displayed, press the + key until 22, press the E key to enter Setup1, press the E key to enter Unit, press the + or - key to select mg/L, and press the E key to confirm.
  2. Output setting: On the main interface, press the E key, code0 is displayed, press the + key until 22, press the E key, press the - key twice to enter output, press the E key twice, select 4-20mA, and press the E key. Then set the value corresponding to 4mA and press the E key; set the value corresponding to 20mA and press the E key to complete.

2. Installation and Maintenance Precautions

Correct installation and maintenance can extend the service life of the transmitter and ensure measurement accuracy.

  • Regular cleaning: The dissolved oxygen probe should be gently cleaned with water regularly every week to prevent contaminants from adhering and affecting measurement.
  • Replace membrane cap: If the membrane cap is found to be damaged, it should be replaced promptly; if the electrolyte is contaminated, it should also be replaced immediately.
  • Cable protection: The probe cable should not be subjected to force, avoiding damage caused by pulling.
  • Sewage applications: Use in municipal sewage is no problem; in industrial sewage, the composition must be clarified, otherwise the membrane cap is easily damaged. H2S, ammonia, benzene, and phenol are harmful to the membrane cap, and in such occasions the membrane cap must be replaced frequently.

Following the above debugging and maintenance methods can ensure the long-term stable operation of the E+H dissolved oxygen transmitter COM223/COM253.