Campbell Scientific CSIM11 pH and ORP Sensors - Manual (Page 15)

CSIM11 pH and ORP Probes
7. Select any other sensors you have, then finish the remaining Short Cut
steps to complete the program. The remaining steps are outlined in Short
Cut Help, which is accessed by clicking on Help | Contents |
Programming Steps.
8. If LoggerNet, PC400 or PC200W is running on your PC, and the PC to
datalogger connection is active, you can click Finish in Short Cut and you
will be prompted to send the program just created to the datalogger.
9. If the sensor is connected to the datalogger, as shown in the wiring
diagram in step 6, check the output of the sensor in the datalogger support
software data display to make sure it is making reasonable measurements.
5. Overview
The CSIM11 and CSIM11-ORP are manufactured by Wedgewood Analytical,
Inc. and wired by Campbell Scientific. They have a plunger-style pH glass
electrode that allow them to be mounted at any angle. Their porous
polytetrafluoroethylene (PTFE) liquid junction is less susceptible to clogging
as compared to conventional reference junctions.
The outer body is made of polyphenylene sulfide (PPS). A titanium ground
rod runs inside their 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 sensors. The life expectancy of these probes is between 6
months to 2 years, depending on the conditions of the water.
These probes are intended for non-pressurized systems and were not designed
for applications above 30 psi. Please contact a Campbell Scientific water
resources application engineer for recommendations on probes suitable for
installations in pressurized pipes.
The CSIM11-ORP probe is identical to the CSIM11 pH probe except the
measuring electrode uses a large surface area platinum band, making the probe
responsive to the electron activity in the fluid. The platinum band helps
prevent organic coating, a common source of error in many types of sensors.
The practical range of the probe is –700 to +1100 mV, which is also the
approximate range of ORP in natural and runoff waters.
Platinum ORP probes should not be used for ozone or peroxide applications,
where platinum will act as a catalyst and the expected potential will not form in
the case of low concentrations. The use of gold, rather than platinum, is
suitable in these applications.
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