YOKOGAWA TB750G, Quick Start Manual, Page: 31 / 37

<5. MAINTENANCE>
5-2
IM 12E01A06-02E
5.2 Calibration
5.2.1 Outline
CALIB STD.CAL ZERO
SPAN
SMP.CAL ZRSPN
ZERO
SPAN
Zero calibration using zero turbidity
water
Span calibration using check block
Span calibration using standard
solution
2-point calibration using
standard solutions
Zero point correction
Sensitivity correction
F5-2E.ai
Calibration
using
filtered
water as
zero
reference
(1)
(2)
(3)
Figure 5.2 Calibration Methods
(1) Select when performing a calibration using 0.2 or 1.0 µm filtered water as zero reference.
(2) Select when performing a 2-point calibration using standard solutions. Use this method to
perform a calibration complying with EPA 180.1.
(3) Select when performing a zero point or sensitivity correction after calibration (1) or (2). This
method is used to adjust the meter reading to reflect the lab data in a grab sample calibration.
Note: The instrument has been pre-calibrated using 0.2 µm filtered water as zero reference at the
factory before shipment.
5.2.2 2-point Calibration Using Turbidity Standard Solutions
A 2-point calibration of the TB750G is performed with turbidity standard solutions equivalent to zero
solution and to span solution. After accepting both zero and span values, the meter calculates a
calibration factor.
When user-prepared zero and span solutions are used for calibrations, the turbidity of diluting water
for calibration should be measured with a calibrated lab turbidimeter in advance. Prepare a formazin
standard solution as a span solution. If the turbidity of diluting water is high against the measurement
accuracy, add the turbidity of diluting water to the nominal turbidity of the prepared formazin standard
solution. Use diluting water as zero solution and a formazin solution as span solution for the
calibration.
Refer to Section 3, “Operation” for concrete operating procedures.