YSI EC300A - Manual (Page 7)

5
5. TDS – Measurement of total dissolved solids (TDS); expressed in grams per liter (g/L).
Carefully observe the units displayed at the far side of the LCD to determine the desired
mode.
CALIBRATION
Calibration setup contains five sections: TDS, Cell, Temperature Coefficient, Temperature
reference, and Conductivity Calibration. To access these sections:
1. Connect the conductivity probe and cable assembly to the unit and turn the unit on. The
screen will display CELL and the cell constant of the conductivity probe.
2. Allow temperature readings to stabilize, then press CAL to enter the calibration mode;
CAL appears on the LCD. Press MODE to sequentially display the following sections:
Note: Press Enter ( ) to accept any values changes in each section and automatically
advance to the next section. If there are no changes, the unit accepts the current value
and proceeds to the next section.
TDS
TDS is determined by multiplying conductivity (mS) by a TDS factor. The default factor value
is 0.65. To change the TDS factor, use the  and  keys to adjust the value between 0.30 and
1.00. Press Enter (
) to save the new value, or press MODE to cancel the change and
display the CELL screen.
CELL
The second screen will display CELL and the current cell value. The default cell value is 5.00
and is displayed in the lower right of the screen. The unit allows a variance of ±0.50 before
displaying an error message. The cell value cannot be adjusted at this screen; calibrating
conductivity is the only way to adjust the cell constant. Press Enter (
) to reset the cell
constant to 5.00 and display the Temperature Coefficient screen.
Note: Be certain to press Enter ( ) to reset the cell constant to 5.00. If MODE is pressed,
the unit retains the previous cell constant and calibrates from a value that is already offset.
Temperature Coefficient
The unit uses the temperature coefficient to calculate temperature compensated conductivity.
The default value is 1.91%. To change the temperature coefficient, use the  and  keys to
adjust the value between 0 and 4.00%. Press Enter (
) to save the new value, or press
MODE to cancel the change and display the Temperature Reference screen.
Temperature Reference
The unit uses the temperature reference value to calculate temperature compensated
conductivity. The default value is 25C. To change the temperature coefficient, use the  and
 keys to adjust the value between 15 and 25C. Press Enter (
) to save the new value, or
press MODE to cancel the change and display the Conductivity Calibration screen.
Conductivity Calibration
1. Immerse the probe in a standard of known conductivity, preferably a standard in the
middle range of the solutions to be measured. Completely submerge the probe without
touching the sides of the calibration container. Shake the probe lightly to remove any air
bubbles trapped in the conductivity cell.