10 days Returnable
1 Year Warranty and 6-7 years nominal Life in a Normal Atmosphere.
- Auto Calibration 2 Point by Soft Touch Buttons
- Set-Point for High and Low Level 2 Nos
- Potential Free Relay Output 2 Relays
- 4-20 MA Output
The setting of Alarm Levels: digital-ph-controller-India; Work Instruction pH Controller
Lower Level Dosing Pump / Alarm Setting: Press the Set button once. Now use the UP and DN buttons to set the Higher level alarm/relay output. If pH Value of the solution goes more than this value relay 1 will turn ON and provide its potential-free contact as output. Now Press / Push ENT button once to save changes
Higher Level Dosing Pump / Alarm Setting: Press the Set button twice. Now use UP and DN buttons to set Lower level alarm/relay output. If pH Value of solution goes Less than this value relay 2 will turn ON and provide its potential-free contact as output. Now Press / Push ENT button once to save changes
Working Principle of pH meter: digital-ph-controller-india
The working of pH meter is based on Nernst equation. Nernst equation derives the relation between the electric voltage with ion concentration. Hence Nernst equation derived for H+ ion concentration is the basis of pH meter. The working principle of pH meter is the potentiometry. While pH meter consists of glass (also called as indicator electrode) and reference electrode. The glass electrode consists of glass membrane. Which is sensitive to hydrogen ion concentration of test sample solution. And the glass electrode potential varies from sample to sample. The reference electrode is standard and has constant potential. The reference electrode does not respond to test sample solution. The pH meter measures and compares the potential difference between both glass and reference electrodes.
While using the Nernst equation. The potential difference is used to measure the hydrogen ion concentration indicating the pH of given solution. Due to the potential difference between two electrodes. The electron flows and generates current. This generated current is measured by voltmeter. The relationship between the potential difference, generated current and pH has been derived. The potential difference of 1 pH is 59.16 mV at 25° C and hence when there is difference of one pH unit, there will be change in voltage by 59.16 mV. This relationship is employed in measuring the pH.
Construction of pH meter:
The pH sensor or probe of modern pH meter is a combined type. Which test and reference electrode are placed into a Glass tube like structure. The combined electrode consist of following parts-
design and Construction of pH meter Probe
1. Glass bulb: It is a sensor that senses the H+ ion concentration. It made from special type of glass and membrane. The glass bulb consists of 0.1 M HCL Solution.
2. Internal electrode: this electrode made by silver chloride.
3. Internal solution: The silver chloride electrode dipped in buffer solution of 0.1 M KCL of pH 4 pH to 7 pH.
4. Reference Electrode: It is also the silver chloride electrode use for reference.
5.Junction: It made from ceramic junction also called as diaphragm. That allows the contact of sample solution and reference electrolyte. It should not disturb the electric connection between both electrodes.
6. Filling hole: It used for refilling the electrolyte if required.
7. Electrode body: The body is from non-conductive glass / plastic material and may coated by epoxy to prevent glass bulb.
While acidic solution is rich in H+ ion concentration. When pH probe dipped in an acidic solution. The H+ ion moves close to the glass membrane of the sensitive glass bulb. Hence Similar reaction occurs inside the bulb, which filled with buffer solution of neutral pH 7 pH. This neutral buffer solution has constant number of Hydrogen ions. The H+ ions present inside the bulb also moves close to glass membrane. Hence this causes the difference in the concentration of hydrogen ion or degree of hydrogen ion. Activity across the membrane causing difference in the potential (voltage). When the hydrogen ion concentration inside the glass bulb is less than the outside solution. Then the given solution is acidic and hence the pH is lower than 7.
When the Hydrogen ions concentration across the membrane similar. Then it called as neutral pH and the pH is equal to 7 pH. While If the concentration of hydrogen ion of inside the bulb. Than outside solution then the given solution is alkaline and the pH is more than 7 pH. Hence pH meter measure the potential difference at both the electrodes and calculate the pH as per the Nernst equation.
- Range : 0.00 to 14.0 pH
- Resolution : 0.10 pH
- Tolerence : +/- 0.15 pH
- Output : No Output Display Only
- Calibration: Auto Calibration Push Buttons on Front Panel; 4pH and 7pH Value
- Input: pH Probe any Brand BNC Connector
- Display: Seven-Segment Bright LED Display
- Operating Voltage: 220 Vac
- Size : 96 * 96 * 110
- Body: PP/ABS
Calibration 7 pH
Dip the Electrode in standard Solution of 7 pH Value, wait for 10 Seconds to stable value
Toch UP push Button for Auto Calibration pH 7.00
Calibration 4 pH
Dip the Electrode in standard Solution of 4 pH Value, wait for 10 Seconds to stable value
Toch DN push Button for Auto Calibration pH 4.00
Push SET and ENT buttons at once for factory calibration setting
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