8.3 USP function (conductive)
According to USP guidelines (“United States
Pharmacopeia”), the Mycom CLM 152 can
measure and monitor non-compensated
conductivity.
The USP option meets the requirement both
for performing a measurement and for
monitoring deviations.
Monitoring is automatic and can be selected
via the Instrument data menu. The
user-selected setting for temperature
compensation has no impact on the
monitoring function.
Measurement requirement for USP
Proceed as follows to carry out the
measurement:
Carry out a non-compensated measurement
and compare the current measured value with
a reference value (see Table) for pure water.
If the measured value deviate upwards, an
alarm is generated via the USP contact.
The measuring transmitter must meet the
following USP requirements for a quasi
substitute compensation:
• Temperature measurement at point of
conductivity measurement
• Round off temperature to next 5 °C step
• Determine the valid monitoring value from
a table (see Table below)
• Alarm is generated if limit is exceeded
• Measuring instrument must be able to
measure uncompensated conductivity /
resistance
• Accuracy 0.1 µS / cm determined with
a simulation resistance with an accuracy
of 0.1 %
• Maximum 2 % deviation of cell constant of
sensor (requirement on the sensor)
• Adequate measuring range dynamics
→ Instrument data
→ USP contact
Temperature [°C] Conductivity [µS/cm] Temperature [°C] Conductivity [µS/cm]
0 0.6 55 2.1
5 0.8 60 2.2
10 0.9 65 2.4
15 1.0 70 2.5
20 1.1 75 2.7
25 1.3 80 2.7
30 1.4 85 2.7
35 1.5 90 2.7
40 1.7 95 2.9
45 1.8 100 3.1
PARAM
Limit configuration Mycom CLM 152
56 Endress+Hauser
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