Omega Engineering Dissolved Oxygen System Oxygen Equipment User Manual


 
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5.8.2 The relay setpoint may be at any place on the scale. To establish the setpoint
proceed as follows:
a) Press CALL to enter the MENU. If the PASSWORD function is enabled, enter
the password then press CALL to illuminate the “%sat/ppm” indicator. If the
PASSWORD function is not enabled, “%sat/ppm” will illuminate at the first press
of CALL.
b) Use the down arrow button to illuminate the PPM LED located to the right side
of the display.
c) Press CALL the required number of times until RELAY A SETPOINT is
indicated. Now use the arrows to make the display read the desired value.
Press ENTER. The display will flash until ENTER is pressed again to confirm
entry. A LED above the display indicates when Relay A is activated.
d) Press RUN to place the instrument on line or press CALL for another menu
selection.
5.9 Relay A Deadband
5.9.1 If you have configured the instrument with the DIP switch on the back of the panel
for falling D.O. you will wish to have the deadband (sometimes called “hysteresis”)
at a higher value than the setpoint. If you have established a setpoint of 3 ppm you
may wish the deadband to be between 6 ppm and 3 ppm. Proceed as follows:
a) Enter the menu and press CALL the required number of times to indicate
RELAY A DEADBAND. Use the arrow buttons to make the display read the
desired value (in this example, 6). Press ENTER. The display will flash until
ENTER is pressed again to confirm the entry.
b) In this example, after the instrument has been returned to RUN, the relay will be
energized when the D.O. falls to 3 ppm and will remain energized until the
reading rises above 6 ppm.
c) When Relay A is activated a LED above the display will be illuminated.
d) Press RUN to place the instrument on line or press CALL for another menu
selection.
5.10 Relay B Setpoint
5.10.1 Relay B Setpoint is configured in the same way as Relay A Setpoint. See Section
5.8. A LED above the display indicates when Relay B is activated.
5.11 Relay B Deadband
5.11.1 Relay B Deadband is configured in the same way as Relay A Deadband. See
Section 5.9.
NOTE: A deadband setting on the wrong side of the setpoint in an invalid entry
which will be indicated by the LED flashing when you return to RUN. To
correct return to the menu and change the deadband setting or, if the
direction of control is the problem, change the position of the relevant DIP
switch. See Sections 4.8 and 5.9.