HYDROLOGICAL SERVICES WLT420, Руководство по эксплуатации

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Hydrological Services Pty Ltd
Wireless Level Transmitter
© Copyright
WLT420 100-8
Issue 1.20 5 Dec, 2007
3. Operation
DIP Switches 1 to 4 on the transmitter and receiver MUST be set the same, so that both units
are set to the same frequency. If multiple units are required in the same vicinity, then set them
to a different frequency. Note that the units use a license free band – however, these bands are
different in Australia and the USA, so make sure DIP switch 4 is set appropriately.
The transmitter sends the 4-20mA current measured, switch settings, battery voltage and the
software revision. This information is all displayed on the receiver LCD.
When the transmitter is set to continuous transmit mode, the receiver LCD recognises this
and stays on permanently. This mode is useful when testing the WLT420. When the
transmitter is set to transmit every 1min, 15 mins or 60 mins then the receiver will
automatically go to sleep, and then automatically wake up the RF circuitry ready to receive
the next expected message – the receiver will stay awake until the message is received. When
a message is received the status LED on the WLT420R Receiver will flash.
3.1 Transmitter LED
The transmitter LED indicates what state the transmitter is in.
LED Description
Flashes every 2 secs Transmitter is asleep
Flashes fast Transducer has power applied – in warm up mode
On Steady Measuring transducer 4-20mA for 1 sec, then transmits result
3.2 LCD Navigation
Press either button to wake up the receiver for 30 secs. The backlighting will also come on for
5 secs. The display will be continually updated as new data is received. Press the scroll
button to step through the most commonly used menu items. Press the select button for 5
seconds to step to special menus as shown.
Use the Set Level menu to set the measured water level. This will automatically calculate an
appropriate offset and add it to the measured 4-20mA level. Scroll to the Offset menu to view
this calculated offset. The Offset may be zeroed by pressing the scroll button for 5 secs.
The Range menu allows the transducer range to be set.
The Last Rx menu shows the last time an RF message was received in hrs:mins:secs. This
will allow you to see if messages are being received correctly. The TxIntvl and Warm Up
menus show you the present positions of the WLT420 transmitter DIP switches.