1. Installation Methods
The CM44X transmitter supports three installation methods, which users can choose according to on-site conditions. Vertical pipe and horizontal pipe installation require additional installation accessories to be ordered.
1.1 Straight Pipe Installation
Suitable for vertical pipes. The installation diagram is as follows:
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1.2 Horizontal Pipe Installation
Suitable for horizontal pipes. The installation diagram is as follows:
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1.3 Wall Mounting
Suitable for wall fixing. The installation diagram is as follows:
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2. Wiring Methods
2.1 Power Wiring
The power wiring methods of CM442 and CM444/448 are different. Please wire correctly according to the model. Pay special attention to the supply voltage marked on the nameplate (220VAC or 24VDC).
CM442 power wiring:
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CM444/448 power wiring:
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2.2 pH Sensor Wiring
The pH sensor wiring steps are as follows:
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- The four cable wires (brown, white, green, yellow) are connected to terminals 87, 88, 97, and 98 respectively.
- The sensor cable shield must be grounded.
- The current output is connected to terminals 31 and 32; the current output is an active output.
Note: Ensure all cable glands are tightened and sealed.
3. Key Functions
The CM44X transmitter uses a combination of soft keys and a navigator. The specific functions are as follows:
- Press soft key: Directly select menu
- Rotate navigator: Move cursor within menu
- Press navigator: Select function
- Rotate navigator: Change value
- Press navigator: Accept new value
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4. Parameter Settings
4.1 Range Setting
Set the "Range Low Value" and "Range High Value" under "Menu/Setup/Output/Current Output".
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4.2 Standard Solution Setting
If E+H original standard solutions are used, there is no need to modify the factory default settings; otherwise, go to "Menu/Setup/Input/CH1: 1:1 pH Glass/Extended Setup/Calibration Settings/Calibration Solution Recognition", change the factory default "Fixed" to "Manual", and enter the pH values of the two standard solutions in "Menu/Setup/Input/CH1: 1:1 pH Glass/Extended Setup/Calibration Settings/Calibration Solution x".
4.3 Transmitter Reset
Under the "Menu/Diagnostics/System Measurement/Reset" menu, select "Factory Default" to reset the transmitter.
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5. Calibration Steps
Go to "Menu/Calibration/pH", select "2-point calibration", and follow the menu prompts to complete calibration. After successful calibration, the slope and zero point are displayed, and it asks whether to adjust the calibration data; after failed calibration, it prompts whether to calibrate again.
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6. Common Fault Codes
Fault codes and their meanings are automatically displayed on the measurement interface; you can go to "Menu/Diagnostics" to view fault codes, and press the "?" key to view the fault meaning.
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7. Sensor Maintenance
Clean the pH sensor regularly; the cleaning interval depends on the working conditions. Recommended cleaning methods are as follows:
- Oil film adhesion: Use an appropriate detergent to remove, such as alcohol, acetone, etc.
- Lime or metal hydroxide adhesion: Dissolve with 3% dilute hydrochloric acid, then rinse thoroughly with clean water.
- Sulfide adhesion (desulfurization flue gas or wastewater treatment plants): Clean with a mixture of 3% dilute hydrochloric acid and thiourea, then rinse thoroughly with clean water.
- Protein adhesion (food industry): Clean with a mixture of 0.5% dilute hydrochloric acid and saturated pepsin, then rinse thoroughly with clean water.
- If the diaphragm of the reference sensor is blocked, use a keyhole file to remove the blockage (not applicable to CPS11 and CPS91 sensors).
- Use a soft brush to remove contamination on the ORP platinum ring, and use a soft cloth to remove contamination on the ORP gold pin.
- Chemical cleaning solutions are strictly prohibited for ORP sensors.
Calibrate the pH sensor at two points regularly; the calibration interval depends on the working conditions. pH sensors must not be exposed to air for long periods and must be stored moist. After prolonged drying, it is recommended to place the sensor in a pH=7 standard solution or 3 mol/L saturated KCl for more than 1 day to activate the sensor.