Calibration Procedure - Orp - Signet 9900 Operating Instructions Manual

Calibration Procedures - ORP
EasyCal Procedure - ORP (one-point calibration)
EasyCal is the fastest and simplest periodic calibration method.
Requires a prepared quinhydrone solution or Light's Solution:
Saturate 50 mL of pH 7 (87 mV) or pH 4 (264 mV) buffers with 1/8 g quinhydrone.
Premixed Light's Solution (476 mV) can be used instead of pH buffers with quinhydrone.
To Calibrate:
Place electrode tip in
saturated pH 7.0 buffer.
pH 7.0 = 87 mV
To exit menus and return to
buttons at the same time.
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).
58 9900 Transmitter
Response:
30s
Allow for stabilization
30 seconds
1
+
Display returns to VIEW
Mode in 10 minutes
To Accept:
to accept
ENTER
1. Go to CAL menu.
2. Press ▼ twice to display
EASY CAL setting.
3. Press ► to begin
one-point EasyCal.
4. Place sensor in solution:
• 87 mV
(7 pH + quinhydrone)
• 264 mV
(4 pH + quinhydrone)
• 476mV
(Light's Solution)
5. Press ENTER.
6. After 30 seconds,
9900 will recognize
current buffer ±80 mV.
7. Press ENTER to accept
mV value.