Endress+Hauser Liquiline M CM42 - Diagnostics, Troubleshooting; General Troubleshooting

Functional Safety Manual
for the Memosens transmitter Liquiline M CM42 SIL
Version: Page:
2.0 14 of 72
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For Orbisint CPS11D (with KSG2-SIL head), the values are for example:
D
pH
/pH = 1.1% + 0.3% = 1.4% (for the temperature range 0°C/32°F to 60°C/140°F,
see safety manual of sensor). That means DpH is 0.2 pH for the temperature range
0°C/32°F to 60°C/140°F.
The complete detailed results are given in the table below about the complete
measuring chain.
The time for a measurement to be visible on the current output is in the worst case
scenario 5 seconds (for example a change from 4 mA to 20 mA and communication
problems, etc.).
This value is only valid for the transmitter. They do not include delays caused by the
cable (almost zero for Memosens cable) or sensor (about 1 second for Orbisint CPS11D,
see safety manual of sensor).
Endress+Hauser pH measuring chain
If you are using a Endress+Hauser pH measuring chain using the SIL Memosens CYK10
cable and the pH glass sensor Orbisint CPS11D (with KSG2-SIL head), the following
figures apply to the whole pH measuring chain:
The time for a measurement to be visible on the current output is in the worst case
scenario <6 seconds, most of the time it is <2 seconds.
The precision depends on the temperature and the current output spreading (for the
values 0.3% and 4.0% used here, see the table and description in chapter 2.2):
Temperature
in Celsius
Temperature
in Fahrenheit
Precision
in pH
(= DpH)
Relative error
on current
output at a
spread of
1 pH
Relative
error on
current
output at a
spread of
14 pH
-20°C – 0°C -4°F – 32°F ±0.30 30%+4%=34% 2.2%+0.3%
0°C – 60°C 32°F – 140°F ±0.20 20%+4%=24% 1.5%+0.3%
60°C – 90°C 140°F – 194°F ±0.30 30%+4%=34% 2.2%+0.3%
90°C – 110°C 194°F – 230°F ±0.40 40%+4%=44% 2.9%+0.3%
110°C – 125°C 230°F – 257°F ±0.45 45%+4%=49% 3.3%+0.3%