YSI 556 MPS - Quick Start Guide - Manual (Page 3)

CONDUCTIVITY, pH, ORP CALIBRATION (6)
1. From the main menu, select Calibrate.
2. Place the correct amount of calibration standard into a clean, dry or pre-rinsed
calibration cup.
3. Immerse the probe into the solution, making sure the sensor to be calibrated is
adequately covered.
4. Allow at least one minute for temperature to stabilize.
5. Select the sensor to be calibrated. For conductivity, a second menu will offer
the option of calibrating in specific conductance, conductivity, or salinity.
Calibration of any one option automatically calibrates the other two. For pH, a
second menu will appear offering the choice of a 1-, 2-, or 3-point calibration.
6. Enter the value of the standard being used. (For pH, always calibrate in the 7
buffer first.) Be certain that the units are correct and press Enter. The current
values of all enabled sensors will appear.
7. Observe the readings and when they show no significant change for
approximately 30 seconds, press Enter. The screen will indicate if the
calibration has been accepted.
8. Press Enter again to return to the Calibrate screen, or, for pH, to continue with
the second point of the calibration.
DO CALIBRATION (6)
The Model 556 offers two options for calibration of dissolved oxygen. The first is an
air calibration method in % saturation. The second is calibrating in mg/L to a solution
with a known DO concentration (usually determined by a Winkler Titration).
Calibration of either option (% or mg/L) will automatically calibrate the other. The
procedure outlined here is the % saturation calibration, the easier of the two methods to
perform.
1. Place approximately 3 mm (1/8 inch) of water in the bottom of the
transport/calibration cup. Screw the transport/calibration cup onto the probe,
engaging only 1 or 2 threads to ensure venting to the atmosphere.
Note: Make sure the DO and temperature sensors are not immersed in
the water.
2. Turn the instrument on to the Run mode and wait 10 minutes for the DO
sensor to stabilize.
3. From the main menu, select Calibrate, then Dissolved Oxygen, then DO %.
4. Use the keypad to enter the current local barometric pressure and press Enter.
The current values of all enabled sensors will appear.
5. Observe the readings and when they show no significant change for
approximately 30 seconds, press Enter. The screen will indicate if the
calibration has been accepted.
6. Press Enter again to return to the DO Calibration screen.