Hanna Instruments HI 221 - Manual (Page 27)

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All instruments are factory calibrated for mV.
Hanna’s pH and ORP electrodes are interchangeable and mV calibration is
not needed when replaced.
If the mV measurements are not accurate, mV recalibration should be carried
out.
For an accurate recalibration, contact your dealer or the nearest Hanna
Customer Service Center or follow the instructions below.
A two or three point calibration can be performed at 0 mV, +600 mV and
+1800 mV.
• Switch off the instrument.
• Attach a mV simulator with an accuracy of at least ±0.1 mV to the BNC
connector.
• Press the RCL and CFM/GLP keys simultaneously and switch the instru-
ment on. After a few seconds, the instrument enters the mV calibration
mode.
• The primary LCD will show the “CAL” and “mV” tags along with mea-
sured mV and the secondary LCD will display 0.0 calibration point.
• Set 0.0 mV on the simulator.
• The “ ” tag will blink on LCD until the reading has stabilized.
• When the reading is stable, the “CFM” tag will blink.
• Press the CFM key to confirm the calibration.
• The instrument will prompt for a second calibration point and will display
600 on the secondary LCD line.
• Set the simulator to +600.0 mV.
• The “ ” tag will blink on the LCD until the reading has stabilized.
• When the reading is stable, the “CFM” tag will start to blink.
• Press the CFM key to confirm the calibration.
• The instrument will prompt for a third calibration point and will display
1800 on the secondary LCD line.
• The two-point mV calibration is now complete.
• Set +1800.0 mV on the simulator.
• The “ ” tag will blink on the LCD until the reading has stabilized.
• When the reading is stable, the “CFM” tag will start to blink.
• Press the CFM key to confirm the calibration.
• The instrument will memorize the calibration and return to measuring
mode.
mV CALIBRATION
(FOR TECHNICAL PERSONNEL ONLY)