Campbell-scientific OBS-5+ Sediment Concentration Monitor and Pressure Instrukcja Użytkownika Pobierz pdf (Strona 15)

OBS-5+ System

6. Operation

6.1 Instrument Setup

6.1.1 Mounting Suggestions

Maximum depth for the OBS-5+ is limited by the installed

pressure sensor. If the maximum depths are exceeded,

the pressure sensor will rupture and the housing will flood.

CAUTION

The depth limits are listed in TABLE 6-1.

TABLE 6-1. Working and Maximum Depths

Pressure Sensor Working Depth Maximum Depth

5 Bar 0 to 50 meters 75 meters

10 Bar 0 to 100 meters 150 meters

20 Bar 0 to 200 meters 300 meters

(1 Bar = 10 dBar ≅ 10 meters of fresh water)

The following precautions should be followed to ensure the unit can function

properly and is not lost or damaged.

• Always orient the unit so that the OBS-5+ sensor “looks” into water clear

of reflective surfaces.

• Pad the endcaps that contact metal with electrical tape, neoprene, or

expanded polyethylene tubes.

• Never mount the instrument by its endcaps or attach anything to them.

This could a cause a leak.

6.1.2 Surveys

The OBS-5+ will usually be towed with a cable harness for surveys. The serial

cable can tow the OBS-5+ without a depressor weight or vane as long as the

connector is strain relieved. Strain relief can be provided by attaching the

cable to the stainless steel housing (FIGURE 4-1) with a cable grip and a

length of 3 mm (1/8 in) wire rope. Install a cable clamp with a 0.5 m wire rope

to the serial cable, and clamp the wire rope to the pressure housing with two

stainless steel hose clamps, providing a small loop of slack cable to absorb

towing forces. The unit can be powered with an external battery, as shown on

FIGURE 6-1, and the serial output can be transmitted by either RS-232 or

RS-485 protocols. The latter protocol is recommended for cable lengths

greater than 25 m. An RS-485/232 serial converter is provided with each unit.

An RS-232 to USB converter is an available option.

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Campbell-scientific OBS-5+ Sediment Concentration Monitor and Pressure Instrukcja Użytkownika Strona 15