Electro-Chemical Devices (ECD) SMS22 - Manual (Page 20)

3.3.2 Graphical Display Screen
This Graphical Display is only available in the Channel 1 menu. It is located one screen down from the
Home Screen. It displays a user assigned output value, for example, 4-20 mA1 vs. time. The Graphical
display variables of which Output to display and what Time interval are used is configured in the Channel
1 Set-Up Menu. See Section 3.3.4, below, for more information on the Set-Up Menu.
3.3.3 Buffer Menu
The Buffer Menus are Calibration Menus. To access the Buffer Menu the cursor must be flashing in front
of the “_Ch 1 Buffer” line. To enter the Calibration screen, simultaneously press both of the Horizontal
CALIBRATE keys. The calibrations are structured for either a single point or two point calibrations.
The first calibration “1 S-- 1.00 ppm” is the “zero point” calibration. The zero point calibration sets a
base millivolt value to a sulfide ion concentration. This is the base point or zero point for a two point
calibration. The Cal 1S-- 1.00 ppm line is also used to Standardize the sulfide reading to a laboratory
determined value. With the Sulfide and pH sensors in a solution of known value, enter that value in the
“1 S-- xx.xx ppm” line. The Cal value, xxx.x mV, is the mV value from the sensor. It can be reset to the
factory default value by “entering” the Cal line.
The second calibration screen is the “slope, mV/decade” calibration. This calibration should use a
solution with a concentration at least 10 times higher than the first calibration solution. Scroll down to
the “2 S-- X.XX ppm” line and enter the value of the calibration solution. The Cal line will display the
new slope, mV/dec.
Sulfide Calibration
Screen Displayed Button Pressed
Ch1 Buffer
Ch1 Setup
Ch1 Status
◄ CALIBRATE ► (enter the calibration menu by pressing
both ◄► simultaneously)
1 S-- 1.00 ppm
Cal -710 mV Press ◄ CALIBRATE ► to start the Cal,
Place sensor in Cal Solution (5 ppm)
1 S-- 1.00 ppm
Cal -730 mV Set the Sulfide value using the CALIBRATE ◄ or ► to move
cursor. Use the ▲or▼ to adjust the integer value.
1 S-- 5.00 ppm
Cal -730 mV MENU SELECT ▼ (accept Calibration)
1 S-- 5.00 ppm
Cal -730 mV MENU SELECT ▼ (move to Cal)
1 S-- 5.00 ppm
Cal -730 mV MENU SELECT ▼(move to Cal 2, Slope)
2 S-- 5.00 ppm
Cal 29.1 mV/dec ◄ CALIBRATE ► (enter Cal Line)
Place sensor in 2
nd Cal Solution (50 ppm)
2 S-- 0.00 ppm
Cal 30.0 mV/dec Set the Sulfide value using the CALIBRATE ◄ or ► to move
cursor. Use the ▲or▼ to adjust the integer value.
SMS-22 Page 11