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Advanced Calibration
Sensors values may be manually calibrated to alternate standards using the
advance calibration features.
OFFSET calibration applies a linear offset adjustment to the value.
SPAN calibration applies an adjustment to the slope of the sensor value.
Note: pH and conductivty are temperature compensated (ATC) sensors. For
accurate calibration, the temperature probe must be in the pH and conduc-
tivity calibration standards. Allow all readings to stabilize before performing
an offset or span calibration operation.
PH
CAL 7 sets the pH 7 calibration (offset.) Cal 7 automatically clears span calibration point prior performing pH
7 calibration.
SPAN calibration is performed typically at pH 4.01 or 10.0
(Always perform pH 7 calibration first.)
CONDUCTIVITY
SET CAL 0 calibrates a dry EC probe if required. (not recommended)
SPAN calibration is recommended at 1413uS. If using ppm standards, ensure the display is in the correct
units.
DiSSOLVED OXYGEN (D.O.)
OFFSET calibration is recommended in zero oxygen solution.
SPAN calibration is recommended at a known DO level or in air.
OXIDATION REDUCTION POTENTIAL (O.R.P.)
OFFSET is recommended at 270mV
SPAN is recommended at 470mV
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CALIBRATE
ADVANCED
CALIBRATION
4-20mA analog outputs may also be calibrated with a positive or negative
offset to compensate for variation in DAC’s/ADC’s. The sensors’ current output
may be incrementally increased or decreased in steps of 0.005mA over a range
of +/-2mA.
1 Offset bit = 0.005mA, Range = +/-400 bits (+/-2mA)
This calibration procedure is optional and only for use with custom PLC appli-
cations.
1. Observe the PLC’s input or data readings.
2. Increase or decrease the offset value to incremenetally adjust the current output until the values match.
Analog Output Calibration
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ANALOG
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