Emerson Rosemount 1057 Instruction Manual page 53

Instruction Manual
LIQ-MAN-1057
3.
7.2.3 Manual Calibration - pH
New sensors must be calibrated before use. Regular recalibration is also necessary. Use manual
calibration if non-standard buffers are being used; otherwise, use auto calibration.
Auto calibration avoids common pitfalls and reduces errors.
The adjacent screen appears after selecting pH Manual cal.
7.2.4 Entering A Known Slope Value — pH
If the electrode slope is known from other measurements, it can be entered
directly in the Model 1057 analyzer. The slope must be entered as the
Slope at 25 °C.
7.2.5 Standardization — pH
The pH measured by the Model 1057 analyzer can be changed to match the
reading from a second or referee instrument. The process of making the two
readings agree is called standardization. During standardization, the
difference between the two pH values is converted to the equivalent voltage.
The voltage, called the reference offset, is added to all subsequent measured
cell voltages before they are converted to pH. If a standardized sensor is placed
in a buffer solution, the measured pH will differ from the buffer pH by an
amount equivalent to the standardization offset.
The following screen may appear if ORP Cal is unsuccessful.
An Offset Error generates the adjacent screen display:
If the ORP Cal is successful, the screen returns to the Cal sub-menu.
Section 7: Calibration
An Offset Error generates the adjacent screen display:
Section 7: Calibration
April 2017
S1: 1.234µS/cm 1.234°C
S2: 12.34pH 1.234°C
S3: 12.34µS/cm 1.234°C
SN pH Auto Cal
Offset Error
Calculated: 61.22mV
Max: 60.00mV
Press EXIT
S1: 1.234µS/cm 1.234°C
S2: 12.34pH 1.234°C
S3: 12.34µS/cm 1.234°C
SN pH Manual Cal
Buffer 1
Buffer 2
S1: 1.234µS/cm 1.234°C
S2: 12.34pH 1.234°C
S3: 12.34µS/cm 1.234°C
SN pH Slope@25°C
59.16 mV/pH
S1: 1.234µS/cm 1.234°C
S2: 12.34pH 1.234°C
S3: 12.34µS/cm 1.23°C
SN Enter Value
07.00pH
S1: 1.234µS/cm 1.234°C
S2: 12.34pH 1.234°C
S3: 12.34µS/cm 1.234°C
SN Standardize
Offset Error
Calculated: 96mV
Max: 60mV
Press EXIT
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