The CSIM11, manufactured by Wedgewood Analytical, measures the full pH range of liquids. It can be submerged in water or inserted into tanks, pipelines, and open channels. The CSIM11 is intended for non-pressurized systems and was not designed for applications above 30 psi. Please contact an application engineer at Campbell Scientific for recommendations on probes suitable for installations in pressurized pipes.
The CSIM11 has a plunger-style pH glass electrode that allows the CSIM11 to be mounted at any angle. Its porous polytetrafluoroethylene (PTFE) liquid junction is less susceptible to clogging as compared to conventional reference junctions.
A titanium ground rod runs inside the PPS outer body to eliminate ground loop errors. An internal amplifier boosts the signal, decreasing signal interference. The amplifier is powered by two internal lithium batteries, and thus does not require any power from the datalogger. These batteries are designed to last the lifetime of the probe.
The reference solutions and bulb configuration are optimized for natural water applications. Alternate reference solutions and bulb configurations are available. Contact Campbell Scientific for pricing and availability.
Note: The CSIM11 uses glass bulb technology which has a life expectancy of around 6 months to 2 years, depending on the conditions of the water.
The CSIM11 requires a differential analog input channel.
Number of FAQs related to CSIM11-L: 8
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Silver is the best electrical conductor of all the metals because it has the lowest electrical resistance. The silver wire, coated in silver chloride, is relatively insensitive to changes in temperature.
A reference electrode can become contaminated when poisoning ions such as lead, iron, chrome, cyanide, or sulfide enter the reference electrode and react either with the silver wire or with the electrolyte solution.
The contamination may not become apparent until the silver-chloride coating is completely dissolved and the electrical potential from the reference electrode has changed greatly. If this occurs, the reference electrode must be replaced.
Cleaning and/or calibration may be required when the measurements are scattered, drifting occurs, or there is physical evidence of fouling. Measurements for pH must be monitored regularly to check for scattering. However, just because the results are scattered does not necessarily indicate the need for an adjustment. For example, there may be a change in the water source that causes the scattering. As a sensor ages, however, the scattering of the measured values tends to increase.
To check the performance of a pH sensor, use it to measure a buffer solution in the correct range. If the value returned is within the specified range, the sensor does not need to be calibrated.
In the event that both alkaline and acidic sample solutions are measured using a single pH sensor, a multipoint calibration is done using three buffer solutions. As in the two-point calibration, the first buffer solution has a 7.0 pH. The second buffer solution should be near in pH value to either the acidic or alkaline sample solution, and the third buffer solution should be near in pH value to the other.
Most Campbell Scientific sensors are available as an –L, which indicates a user-specified cable length. If a sensor is listed as an –LX model (where “X” is some other character), that sensor’s cable has a user-specified length, but it terminates with a specific connector for a unique system:
If a sensor does not have an –L or other –LX designation after the main model number, the sensor has a set cable length. The cable length is listed at the end of the Description field in the product’s Ordering information. For example, the 034B-ET model has a description of “Met One Wind Set for ET Station, 67 inch Cable.” Products with a set cable length terminate, as a default, with pigtails.
If a cable terminates with a special connector for a unique system, the end of the model number designates which system. For example, the 034B-ET model designates the sensor as a 034B for an ET107 system.
Not every sensor has different cable termination options. The options available for a particular sensor can be checked by looking in two places in the Ordering information area of the sensor product page:
If a sensor is offered in an –ET, –ETM, –LC, –LQ, or –QD version, that option’s availability is reflected in the sensor model number. For example, the 034B is offered as the 034B-ET, 034B-ETM, 034B-LC, 034B-LQ, and 034B-QD.
All of the other cable termination options, if available, are listed on the Ordering information area of the sensor product page under “Cable Termination Options.” For example, the 034B-L Wind Set is offered with the –CWS, –PT, and –PW options, as shown in the Ordering information area of the 034B-L product page.
Note: As newer products are added to our inventory, typically, we will list multiple cable termination options under a single sensor model rather than creating multiple model numbers. For example, the HC2S3-L has a –C cable termination option for connecting it to a CS110 instead of offering an HC2S3-LC model.
Many Campbell Scientific sensors are available with different cable termination options. These options include the following:
Note: The availability of cable termination options varies by sensor. For example, sensors may have none, two, or several options to choose from. If a desired option is not listed for a specific sensor, contact an application engineer at Campbell Scientific for assistance.
The recommended calibration method listed in a specific pH sensor’s instruction manual should be followed to guarantee the best results. Calibration must be performed correctly to ensure accurate and repeatable measurements. Before performing calibration, the pH sensor should be cleaned.
Calibration is commonly done using a known-value pH solution called a buffer. The buffer solution is formulated to resist pH changes caused by external contaminants. However, the pH of the buffer solution changes as the temperature changes. To compensate for this, manufacturers list the pH of the buffer solution at various temperatures on the buffer solution’s bottle so that the correct value for calibration is selected.
The most common calibration method is a two-point calibration using two buffer solutions. Each buffer solution has known and accurate pH values at different temperatures. The buffers used should be based on the normal measurement range that the pH sensor operates in for the application. One buffer solution should have a 7.0 pH. The second buffer solution should have a pH that is near the expected pH value of the sample solution.