Campbell Scientific OBS500 Smart Turbidity Meter with ClearSensor Technology - Manual (Page 13)

OBS500 Smart Turbidity Meter with ClearSensor™ Technology
• The most important general precaution is to orient the unit so that the
OBS sensor looks into clear water without reflective surfaces. This
includes any object such as a mounting structure, a streambed, or
sidewalls. The backscatter sensor in the OBS500 can see to a distance of
about 50 cm (20 in) in very clean water at angles ranging from 125° to
170°. The side scatter (SS) sensor can only “see” to about 5 cm (2 in) at
90°.
• The sensor has ambient-light rejection features, but it is still best to orient
it away from the influence of direct sunlight. Shading may be required in
some installations to totally protect from sunlight interference.
• Nearly all exposed parts of the instrument are made of Delrin, a strong but
soft plastic.
Always pad the parts of the OBS500 housing that will
contact metal or other hard objects with electrical tape or
neoprene.
• Mounting inside the end of a PVC pipe is a convenient way to provide
structure and protection for deployments. The OBS500 will fit inside a
2-in. schedule 40 PVC pipe.
The most convenient means for mounting the unit to a frame or wire is to use
large, high-strength nylon cable ties (7.6 mm (0.3 in) width) or stainless steel
hose clamps. First cover the area(s) to be clamped with tape or 2 mm (1/16 in)
neoprene sheet. Clamp the unit to the mounting frame or wire using the
padded area. Do not tighten the hose clamps more than is necessary to produce
a firm grip. Overtightening may crack the pressure housing and cause a leak.
Use spacer blocks when necessary to prevent chafing the unit with the frame or
wire.
Mounting Example:
FIGURE 4-1. Use strain relief to keep stress off the cable and provide
extra security
CAUTION
3