Electro-Chemical Devices (ECD) L20 - Manual (Page 7)

Operational Procedures
A. Buffer Set Selection
The Model L20 meter has two buffer sets: 7.00, 4.01, 10.01pH and
6.86, 4.00, 9.18 pH. The meter is factory pre-set at 7.00, 4.01 and
10.01 pH. To change the buffer set, turn off the unit, then press and
hold the “Stand” key while turning on the unit again.
[Note: There is no need to repeat this procedure every time the unit
is power up unless one decides to change the buffer settings.]
B. pH Calibration
The Model L20 uses 2-point or 3-point calibration. The first point
must be 6.86/7.00, and the second point can either be 4.00/4.01 or
9.18 / 10.01.
Calibration with an ATC/Temp probe in the pH-
AUTOLOCK mode
1. Turn the unit on. Press “Clear” key for 2 seconds, all LCD
elements will light up. The meter clears all calibration
values stored in internal memory.
2. Connect the pH electrode to the BNC connector and the
ATC/Temp probe to the ATC/Temp connector of the unit:
“ATC” icon will light up. “pH” icon and “AUTO” icon light
up. The buffer set icon will flash.
3. Rinse the pH and ATC/Temp probes in distilled water and
immerse them in the first buffer solution (either 7.00 or
6.86). Allow temperature reading to stabilize, then press
and hold “Stand” key for 5 seconds to calibrate. The
“WAIT” icon will flash until the unit detects a stable
reading. Once the unit calibrates the first point, the
selected buffer remains lit up while the remaining two
buffers start to flash. The unit is ready to be sloped at the
second buffer.
[Note: If the first buffer solution is 7.00 or 6.86, at this
moment, press the “Mode” key. The unit will exit the
calibration mode. Single point calibration is complete. If
the first buffer solution is 4.00, 4.01, 9.18 or 10.00, at this
moment, the unit will automatically exit the calibration
mode. Single point calibration is complete.]
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