|
2-Wire pH/ORP Analyzers
Models PH202G, PH202S
   |
|
|
|
|
|
Flexibility, reliability, low maintenance and low installation costs are among the benefits of the EXA PH202 pH/ORP analyzers. Designed to meet the exacting requirements of measuring pH and ORP in the modern industrial environment, it contains many features to ensure peak precision whatever the application.
This 2-wire (loop powered) analyzer is housed in a robust IP65 field mountable case. The need for expensive cabling is minimized. The famous EXA sensor diagnostics are enhanced by an improved impedance check, and the addition of a logbook feature. Calibration history is available in the display, and full logbook data is accessible through the HART bi-directional communication link, and is used to store important configuration, calibration and diagnostic data. Prediction of sensor failure is possible by reference to the logbook.
Microprocessor-aided calibration uses internal buffer tables and stability checking to ensure maximum accuracy with minimum effort. Process temperature compensation enhances accuracy in applications where the influence of temperature is seen in process pH changes. pH and ORP or rH measurements can be made simultaneously when an appropriate sensor combination is used.
Yokogawa has implemented three leading process Fieldbus technologies in their 202 series: HART, Foundation Fieldbus H1 and Profibus PA. All transmitters are provided with the important and widely used Device Description files that provide information on parameters and other data in each device, as well as the ability to include algorithmic relationships such as calibrations.
|
|
|
* Universal pH/ORP.
* Possible to input high impedance reference electrode.
* On-line sensor checking.
* Process temperature compensation.
* Differential input amplifier with equipotential screening.
* Freely configurable ITP, slope and assymetry.
* Easy to use EXA control panel.
* Password protection for all levels of software.
* HART®, PROFIBUS-PA, FOUNDATION Fieldbus H1 communications.
|
|
|
| Measuring principle |
Glass electrode method |
| Input ranges |
pH: -2 to 16 pH
ORP: -1500 to 1500 mV
rH: 0 to 55 rH
Temperature: -30 to 140 deg C |
| Output ranges |
pH: Min. 1 pH, Max. 20 pH
ORP: Min. span 100 mV, Max. span 3000 mV
rH: Min. 2 rH, Max. 55 rH
Temperature: Min. 25 deg C, Max. 200 deg C |
| Output Signal |
4 to 20 mA DC loop powered, isolated from input
With the possibility of 21 mA "FAIL" signal (burn up) and 3.6 mA (burn down when HART or distibutor comm. is non-used), 3.9 mA (burn down when HART or distributor comm. is used). |
| Temperature compensation |
Range: -30 to 140 deg C (for 8k55 sensor -10 to 120 deg C).
Sensor types: Pt100, Pt1000, 3 kΩ RTC, 5.1 kΩ PTC, 8.55 kΩ NTC, 350 Ω PTC, 6.8 kΩ PTC, 10 kΩ PTC. Automatic or manual compensation to Nernst equation. Process compensation by configurable coefficient. Adjustable ITP (Iso-thermal point of intersection). |
| Calibration |
Semi-automatic, using tables in transmitter for pH 4, 7 & 9 buffer solutions, or using user-defined tables, with automatic check of measurement stability.
Manual, using standard sample, by correcting reading to value of standard.
Calibration by slope and asymmetry potential setting. (IEC60746-2) |
| Communication |
HART®, PROFIBUS-PA, FOUNDATION Fieldbus H1 |
| Ambient temperature |
-10 to 55 deg C |
| Humidity |
10 to 90 % RH (Non-condensing) |
| Explosionproof |
FM, ATEX, CSA, IECEx |
| Display |
Custom liquid crystal display, with a main display of 3 1/2 digits 12.5 mm high. |
| Power supply |
Nominal 24 volt DC loop powered system.
PH202G: 17 to 40 V
PH202S: 17 to 31.5 V |
|
|
The specifications are expressed with simulated inputs.
pH- Linearity
Repeatability
Accuracy |
±0.01 pH
±0.01 pH
±0.01 pH |
ORP- Linearity
Repeatability
Accuracy |
±1 mV
±1 mV
±1 mV |
|
|
|
| · |
2-Wire pH/ORP Analyzers PH202G, PH202S |
|
|
|
|
