YSI pH100A - Manual (Page 6)

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and region, and users are expected to understand and follow the battery disposal
requirements for their specific locale.
KEY FUNCTIONS OF THE MODEL pH100A
1. : Turns the unit ON or OFF. The pH calibration values are not erased when the unit is
turned off. The unit powers up in the same status as when it was turned off. When the
unit is not in use, turn it off to save battery life. The instrument has a 30 minute auto shut
off feature when not in use. For long term storage, remove the batteries.
2. MODE: Selects display mode. Press MODE to sequentially display pH-AUTOLOCK ,
mV-AUTOLOCK , pH, mV, Recall and Delete. Calibration values are not affected by
changing display mode.
3. STAND and SLOPE Keys: Used for dual-point pH calibration of the unit. Press and hold
STAND while turning on the power to change buffer sets.
4.
 and  Keys: Press to enter temperature values in manual (MAN) mode. These keys are
inoperative when operating in ATC mode.
5. MEA./EFF.: Press to release the unit from AUTOLOCK status when operating in pH-
AUTOLOCK or mV-AUTOLOCK mode. Press and hold for 5 seconds to display the
electrode efficiency.
6. ESC: Press once to store data. Press and hold for 2 seconds to clear the unit when an
error message appears; it clears all calibration values stored in internal memory. When
ESC is pressed for 2 seconds, all LCD elements light. After about 2 seconds, the unit
enters pH-AUTOLOCK mode. “AUTOLOCK” displays and “STAND” begins to flash
indicating the need for calibration.
THE LCD DISPLAY
1. WAIT: Displays while unit waits for a
stable reading or end point sensing.
2. BAT: Low battery indicator.
3. ATC/MAN: “ATC” displays if an ATC
probe is connected. Otherwise, “MAN”
displays.
4. STAND/SLOPE: “STAND” or “SLOPE”
remains steady if the parameter has been
calibrated. If either one has not been
calibrated, it flashes.
5. AUTO: Autolock mode indicator.
6. HOLD: Indicates a reading is frozen during Autolock mode.
7. EFF%: Displays when the user views electrode efficiency. It is recommended to replace the
electrode when efficiency is less than 75%.
8. pH/mV : Unit and mode indicators.
9. Main display for pH, mV and probe efficiency values.
10. C: Temperature display.
OPERATIONAL PROCEDURES
Buffer Set Selection
The pH100A has two buffer sets: 7.00, 4.01, 10.01 pH and 6.86, 4.00, 9.18 pH. The factory
default is buffer set 7.00, 4.01, and 10.01. To change the buffer set, turn off the unit and
place the sensor in buffer 7.0. Next, turn the unit on while pressing and holding the STAND
key. Continue pressing the STAND key until the unit beeps. If the unit is uncalibrated and in
pH mode, it displays “7.00” if the first set is active, and “6.86” if the second set is active.
Figure 1. LCD Display
STAND
SLOPE ATC
MAN
B
A
T
AUTO
WAI T HOLD EFF%
pH
m V
1
2
3
4
5
6
7
8
9
10
C