Ahlborn ALMEMO 2290-8, Руководство по эксплуатации

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Zero Point Adjustment
Many sensors must be adjusted at least once or at regular intervals to
compensate for instabilities. For this purpose, a specific
zero point
adjustment is available, in addition to the ´Set Measured Value to Zero´
mentioned above, as some sensors require an additional scaling (e.g. pH
probes). In this function the zero point error is not stored as base value but as
zero point correction (special cases and slope correction, see 6.5). In this case,
the locking mode must be set below 4 (see 6.7). The zero point correction is
performed using the following keys:
Function:
MEAS. VALUE
Zero point adjustment: ,
ENTER
±
If a base value is programmed the measured value is not indicated
as zero but as the negative base value after the adjustment.
For some sensors special functions are available in this context:
1. With pH probes, if the two keys
ENTER
and
F
are pressed during switch-on,
the locking is only temporary, i.e. until the device is switched off and set to
3. An undesired adjustment can then be avoided.
2. Dynamic pressure probes are very delicate and should be adjusted in an
unpressurized state before each use (i.e. disconnected hoses or Pitot tube
out of flow). The correction value must be entered before the conversion
'pressure-to-velocity' is performed. For the ranges L840 and L890 an
adjustment is possible even if the channel is locked.
The zero point error is temporarily being written into the calibration offset
until the switch-off is performed.
3. With the following sensors, a slope adjustment is performed in the same
way for the corresponding calibration value:
pH-probe: ZA 9610-AKY: pH4 or pH10
Conductivity: FY A641-LF: 2.77 mS/cm,
FY A641-LF2: 147 uS/cm
FY A641-LF3: 111.8 mS/cm
O
2
saturation: FY A640-O2: 101 %
32 ALMEMO
®
2290-8
Continuous Measurement of a Measuring Point