BABBITT LS8500, Owner'S Manual

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www.babbittinternational.com Reference Manual
2021
7
2. THEORY OF OPERATION
The LS8500 employs a radio frequency (RF) balanced impedance bridge circuit to detect if the sensing
element is in contact with the material that is to be sensed. When material is not in contact with the sensing
element, the bridge is balanced by turning the adjustment pot to find the threshold where the red led goes out.
When material is in contact with the sensing element, the bridge becomes unbalanced and the comparing
circuit realizes the change. This causes the relay to change state.
3. INSTALLATION
3.1 Inspection
Carefully unpack the LS8500 from the shipping box and check each item against the packing list before
destroying any packing material. Visually inspect for any damage that may have occurred during shipping.
Please advise the factory or your local distributor of any damage.
A complete unit should consist of the following:
1. An explosion proof enclosure with flange attached
2. A transmitter module in the explosion proof enclosure
3. The LS8000/R receiver card
4. A plastic snap track to mount the receiver card
3.2 Bench Test
*THIS IS AN EXCELLENT TIME TO TEST AND BECOME FAMILIAR WITH THE TIME DELAY
IF IT IS TO BE USED IN YOUR APPLICATION. (See calibration instructions, section 7.1 and 7.2)
On the bench, hook up the appropriate power to L1 and L2. The operating voltage of the LS8500 is
marked on the power supply board. Hold the unit so that nothing is touching the flange sensing element.
Turn the sensitivity POT CW (right) until the RED LED comes on, then CCW until the RED LED goes
out. Touch the sensing element and the RED LED should come on. This simulates product touching the
sensing element. If a timing mode has been selected it will operate as if installed.
NOTE: The timing mode can be adjusted when checking the unit, but the sensitivity adjustment
MUST BE MADE AFTER the unit is installed where it will be used.
CAUTION: ALL INSTALLATION AND WIRING MUST CONFORM TO NEC AND ALL
OTHER LOCAL ELECTRICAL CODES. TAKE SPECIAL CARE IN OBSERVING
HAZARDOUS AREA SAFETY PROCEDURES. WE ASSUME NO LIABILITY FOR
IMPROPERLY INSTALLED OR WIRED UNITS.