Signet 9900 Operating Instructions Manual page 59

Calibration Procedures - ORP
Manual Calibration Procedure - ORP
Requires prepared buffers and a prepared quinhydrone solution:
Saturate 50 mL of pH 4 (264 mV) and 7 (87 mV) buffers with 1/8 g quinhydrone or
Light's Solution (476 mV).
(System calibration is possible with two known ORP solutions,
but use a buffer close to your own process value).
To Calibrate:
Place electrode tip in
saturated pH 7.0 buffer.
pH 7.0 = 87 mV
To Set Slope:
Place electrode tip in
saturated pH buffer two
pH units different than
standard.
pH 4.0 = 264 mV
To Set Calibration Date:
NOTE: ORP solutions made with quinhydrone are very unstable and
may not read properly once exposed to air for a prolonged time.
These solutions must be disposed of within an hour.
The solution can be used for calibrating more than one sensor.
However, the solution must remain free of debris and must not be
diluted by rinse water from previous calibrations.
Acceptable ranges for the readings are ± 80 mV (i.e., 87 ± 80 mV).
30s
ENTER
Allow for stabilization
30 seconds to
several minutes
to accept
30s
ENTER
Allow for stabilization
30 seconds to
to accept
several minutes
+
Display returns to
VIEW Mode
To Change Reading:
ENTER
to accept
To Change Reading:
to accept
ENTER
Single-point calibration
sets STANDARD only;
Signet recommends a
two-point calibration to
set SLOPE in addition
to STANDARD.
Quick Manual Calibration
Procedures:
1-Point Calibration:
1. Set solution standard.
2-Point Calibration
(recommended):
1. Set solution standard.
2. Set solution slope.
9900 Transmitter 59