Endress+Hauser CCS50D, Operating Instructions Manual

Page: 28 / 52

Commissioning CCS50D
28 Hauser
Requirements
The sensor reading is stable (no drifts or unsteady values for at least 5 minutes), and the
medium is stable. This is normally guaranteed once the following preconditions have been
met:
• The polarization period has elapsed.
• The flow is constant and within the correct range.
• The sensor and the medium are at the same temperature.
• The pH value is within the permitted range.
• Optional:
For zero point adjustment: electrolyte has been replaced (→  34)
Zero point adjustment
A zero point adjustment is not required due to the zero point stability of the membrane-
covered sensor.
However, a zero point adjustment can be performed if desired.
1. To perform a zero point adjustment, operate the sensor for at least 15 minutes in
chlorine-free water, using the assembly or protection cap as a vessel.
2. Alternatively, perform the zero point adjustment using the zero point gel
COY8→  40.
Slope calibration
Always perform a slope calibration in the following cases:
• After replacing the membrane cap
• After replacing electrolyte
• After the membrane cap has been screwed back on
1. Ensure that the temperature of the medium is constant.
2. Take a representative sample for the DPD measurement. This must be done in close
proximity to the sensor. Use the sampling tap if available.
3. Determine the chlorine dioxide content using the DPD method.
4. Enter the measured value into the transmitter (see Operating Instructions for
transmitter).
5. To ensure greater accuracy, check the calibration several hours or 24 hours later using
the DPD method.