Hach 900 manual Instrument Description, Interface Connectors, Receptacle Caps, General Information

Section 2 General Information

2.1 Instrument Description

The instrument is designed to automatically collect and preserve samples from a liquid source. The sampler is suitable for collection of conventional and toxic pollutants and suspended solids.

The sampler collects samples on either a timed cycle basis, or in proportion to flow when used in conjunction with a flow meter (flow meter connected to the auxiliary connector). In the timed cycle mode, the interval between samples is controlled by an integral quartz crystal clock. The sample interval may be set from 1 to 9999 minutes, in one minute increments.

In the flow proportional mode, via an external flow meter, the interval between samples may be set from 1 to 9999 flow pulses, in one pulse increments. where each pulse represents a specific flow volume interval.

The number of minutes or flow intervals remaining unit the next sample is shown on the control display. The program can be delayed by entering the desired starting time and date on the sampler keypad.

The sampler utilizes a high speed peristaltic pump, for collection of the sample liquid. The pump body is constructed of impact and corrosion resistant plastic. Tubing is held firmly in place by the pump body haves-no clamps are required. The intake line is air purged before and after each sample. The duration of the pre and post sample purge automatically compensates for different intake line lengths. The pump tubing is 0.95 cm (3/8 in.) ID X 0.32 cm (1/8 in.) wall medical grade silicone rubber. Although the pump is capable of vertical lifts up to 8.2 m (27 ft), lifts greater than 6.7 m (22 ft) are not recommended unless the Remote Pump option is utilized. The pump produces a sample transport velocity of 1 mps (3.3 fps) at 1 m (3 ft) vertical lift. The sample is under pumped flow at all times from the source stream to the sample container, thereby keeping solids in suspension.

2.2 Interface Connectors

The interface connectors are located on the left side of the controller housing.

The sampler comes standard with two interface receptacles:

•12 V dc (Power Input)

•Auxiliary (Multi-purpose input/output port)

2.2.1 Receptacle Caps

Interface receptacles are covered with push-on receptacle caps. These caps protect the connector pins from dirt and moisture and should be attached to any receptacle not in use.

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8544intro.fm	General Information