Myron L CTCIITD - Manual (Page 25)

B. CALIBRATION PROCEDURES
All Myron L CTCII Chemical Treatment Controllers are factory
calibrated prior to shipping and are ready to install without further
calibration. Calibration should be checked occasionally with
the internal Electronic Calibration Test switch (EC) to ensure
continued accuracy.
The following procedures are provided in the event that
recalibration becomes necessary. The only equipment required
are a tweaker or small screwdriver, and standard solution.
Refer to Figure V.A.1. to locate the components described in this
section.
WARNING: When performing calibration procedures, the
technician must take extreme care to avoid contacting the
circuitry other than the CALibration control. Failure to do so
could result in damage to the equipment, property and/or
personal injury.
1. ELECTRONIC CALIBRATION
(CIRCUIT ONLY)
This method is faster than the method using standard solution,
but it does not include the sensor. Therefore, it should be used
only in applications where the chance of sensor contamination or
damage are slight.
The Set Point control will be used to check the calibration.
NOTE: The DISplay calibration control (if display is installed)
has been set and sealed prior to leaving the factory, and under
normal conditions will not require readjustment. This allows the
user to observe the panel display (if installed) to visually set
the electronic value. If the DISplay calibration control has been
adjusted it will be necessary to, first, verify or adjust the Set Point
Control Calibration as described in “Set Point Control Calibration”
below.
a. Set Point Control Calibration
1. Ensure power is OFF.
2. Using a Phillips Head screwdriver remove the four (4)
screws on the clear cover.
3. Remove clear cover.
4. The front panel is held in place with hook & loop strips
on each side. By carefully lifting at the slot on the top,
the front panel will pull toward you. Do not pull more than
about 8 inches/20CM.
DO NOT pull on control knob(s).
5. Rotate the front panel down so that the back side is
facing you. The Circuit Board is mounted to the back of
the front panel.
6. Turn power ON.
CAUTION: When handling Circuit Borad, DO NOT touch
component side. Electrical shock may occur.
7. Press and hold the Electronic Calibration switch (EC).
8. Rotate Set Point Control from “0” toward EC. At EC the
relay should click, and the LED should change from RED
to GREEN. If not, set Set Point control to EC and adjust
the CALibration control.
Models with 3 1/2 digit LCD.
The display should indicate 2.50.
If not, adjust the DISplay calibration control.
9. Turn power OFF.
10. Re-install front panel and cover as described in
“REASSEMBLY”.
11. To operate, turn power ON.
b. 0-10VDC Recorder Output Calibration
For output voltages other than 10VDC, substitute as required, i.e.
5.00VDC or 2.00VDC per Section II.F.2.
Requires a DVM set to DC Volts.
1. Ensure power is OFF.
2. Attach DVM to RECORDER output connection.
3. Turn power ON.
4. Press and hold the Electronic Calibration switch (EC).
5. The DVM should indicate 5.00VDC.
6. If not, adjust CALibration control until DVM indicates
5.00VDC.
7. Verify the set point control is set at EC point. If not,
loosen knob on shaft and reset to EC.
8. Verify the display (if installed) is indicating a reading
of 2.50. If not, adjust DISplay control until a full scale
reading is displayed.
9. Turn power OFF.
10. Re-install front panel and cover as described in
“REASSEMBLY” or continue.
11. To operate, turn power ON.
2. CALIBRATION USING
STANDARD SOLUTION
The best method of recalibrating your conductivity/TDS CTCII
Chemical Treatment Controller is with a NIST traceable Standard
Solution (available from the Myron L Company). Because it
includes the sensor, the entire system is recalibrated.
The following procedure describes the easiest method for
standard solution calibration of your Conductivity/TDS CTCII
Chemical Treatment Controller. We recommended using Myron L
442-3000 Standard Solution. This standard solution will calibrate
both Conductivity µS (at 3900 µS) and TDS ppm (at 3000 ppm)
modes.
1. Rinse thoroughly, and fill a clean glass beaker with the
standard solution.
2. Place sensor in the beaker of standard solution. The
level of standard solution must be high enough to cover
at least 1/2” above the electrodes.
3. Slowly shake the sensor to remove air bubbles from the
electrodes.
4. Allow 5-10 minutes for temperature to equilibrate. For
the quickest and the best results, both the sensor and
solution should be at the same temperature.
5. Turn power ON.
6. Rotated the Set Point control to 3900 for Conductivity
modes or 3000 for TDS modes. The relay should click
and the LED will change from RED to GREEN. Display
models (standard 3 1/2 digit).
The display should match the value of the standard
solution, 3900 µS (displayed as 3.90) or 3000 ppm
(displayed as 3.00).
If the reading is different, adjust CALibration control
on the main circuit board until the reading matches the
solution value.
7. After adjustment, turn power OFF.
8. Re-install front panel and cover as described in
“REASSEMBLY”.
9. To operate, turn power ON.
! CAUTION - READ FOLLOWING CAREFULLY
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