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Maintenance – Campbell Scientific AL200 ALERT2 Encoder, Modulator, and Sensor Interface User Manual

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AL200 ALERT2 Encoder, Modulator, and Sensor Interface

Under normal operation, the AL200 will obtain a GPS fix and measure sensors

based on its configuration. When the sensors are measured and an event

threshold has been exceeded, the AL200 will wait until its designated time slot

and then power up the radio and transmit the data to a repeater or base receiver.

Concentrated ALERT data is retransmitted using the ALERT

concentration protocol.

Event-driven rainfall data is transmitted as a tipping bucket rain gauge

report with a sensor ID of zero (0).

Other event-driven sensor data is transmitted as a general sensor

report. If events for multiple sensors are detected in the same frame,

then multiple general sensors reports will be transmitted.

A scheduled self-report is transmitted as a multi-sensor report.

If a GPS fix cannot be obtained and the AL200’s internal clock cannot be

disciplined, the device will transmit data during random slot times throughout

the frame interval in an attempt to not continuously interfere with adjacent time

slots.

When connected to the AL200 with the Device Configuration Utility, the

AL200 will power up and measure the attached sensors on the

Configuration

Sensor Scan Interval located on the Sensor Data Monitoring tab, but

transmissions will be suppressed.

9. Maintenance

It is a good idea to periodically check the sensor inputs against known values to

ensure that the device is still within the specified accuracy ranges. Connecting

to the AL200 with a USB cable will force the AL200 to measure the attached

sensors on the

Configuration Sensor Scan Interval. This will allow the user

to quickly see how sensors respond to changes. Upon disconnecting from the

device, the AL200 will resume its

Sensor Scan Interval.

Pressing the test button for three to six seconds will trigger a test transmission

containing the latest data available to the AL200. Pressing the button for

longer than six seconds will cause the AL200 to generate a test tone and sustain

it for five seconds. This test tone can be used to check the forward and

reflected power of the radio.

Consult your sensor and radio manufacturer’s manuals for recommended

maintenance of these devices.

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