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Section 5 System Startup
5.1 General Operation
Plug the sensor into the unpowered controller by aligning the orientation tab on
the cable connector with the channel in the controller connector. Push in and turn
to secure the connection. Tug gently to check the connection.
After all plumbing and electrical connections have been completed and checked,
place the head on the body and supply power to the system. Ensure the head is
seated on the body when power is applied, since dark readings are measured at
this time. If power is applied while the sensor head is off the turbidimeter body,
cycle the power with the sensor head on the body.
The first time a controller is powered up, a language selection menu will appear.
The user must select the correct language from the displayed options.
Use the UP and DOWN keys to highlight the appropriate language and press
ENTER to select.
Following language selection and upon power-up, the controller will search for
connected sensors. The display will show the main measurement screen. Press
the MENU key to access the menus.
5.2 Starting Sample Flow
Start sample flow through the instrument by opening the sample supply valve.
Allow the turbidimeter to run long enough for the tubing and body to become
completely wetted and the reading on the display to stabilize. One to two hours or
longer may be required initially for complete stabilization. Allow measurements to
become stable through adequate conditioning before completing instrument
settings or performing calibrations.
5.3 Sensor Calibration and Verification
The manufacturer offers two EPA-approved calibration methods one using user-
prepared formazin and the other using StablCal® stabilized formazin. Two
verification methods (wet and dry) are also offered.
The 1720E Turbidimeter is factory-calibrated using StablCal
®
Stabilized Formazin
before shipment. The instrument must be recalibrated before use to meet
published accuracy specifications. In addition, recalibration is recommended after
any significant maintenance or repair and at least once every three months during
normal operation. The turbidimeter body and bubble trap must be thoroughly
cleaned and rinsed before initial use and prior to each calibration.
Tips to achieve the most accurate calibrations:
• Optimum performance is achieved when calibration is performed in the
turbidimeter body. Accurately prepare the standard then add it to the
turbidimeter body at the appropriate step in the procedure. Do not prepare the
standard in the body.
• Stop sample flow, drain, and clean the turbidimeter body before beginning the
calibration procedure.
• Always clean the photocell window per the instructions in section 6.4.2 on
page 48. Rinse the photocell with deionized water and dry with a soft, lint-free
cloth before calibrating.
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