ST-20 Argos Satellite Transmitter Revision: 6/07 Picture of ST-20 C o p y r i g h t © 2 0 0 6 - 2 0 0 7 C a m p b e l l S c i e n t i f i c , I n c .
Warranty and Assistance The ST-20 ARGOS SATELLITE TRANSMITTER is warranted by CAMPBELL SCIENTIFIC, INC. to be free from defects in materials and workmanship under normal use and service for twelve (12) months from date of shipment unless specified otherwise. Batteries have no warranty. CAMPBELL SCIENTIFIC, INC.'s obligation under this warranty is limited to repairing or replacing (at CAMPBELL SCIENTIFIC, INC.'s option) defective products.
ST-20 Table of Contents PDF viewers note: These page numbers refer to the printed version of this document. Use the Adobe Acrobat® bookmarks tab for links to specific sections. 1. Overview.......................................................................1 1.1 1.2 1.3 1.4 1.5 Specifications............................................................................................1 Serial Port .................................................................................................
ST-20 Table of Contents Figures 1-1. ST-20 Argos Satellite Transmitter.......................................................... 1 1-2. ST-20 with CR1000 Datalogger in Enclosure ........................................ 2 Table 1-1. ST-20 Serial Port Configuration.............................................................
ST-20 Argos Satellite Transmitter 1. Overview The ST-20 is a certified Argos PTT satellite transmitter for use with Campbell Scientific, Inc. CRBasic dataloggers. Service Argos data transceivers fly aboard two NOAA polar orbiting satellites. With an orbit altitude close to 800 kilometers, the satellites are at a relatively low orbit. The low orbit allows for low transmit power, low battery power requirements and the use of an omnidirectional antenna.
ST-20 Argos Satellite Transmitter TABLE 1-1. ST-20 Serial Port Configuration Pin number 1 2 3 4 5 6 7 8 9 Function +5 volts Ground NC TXD (data out) NC SDE (input) CLK/HS (input) +12 volts RXD (data in) FIGURE 1-2.
ST-20 Argos Satellite Transmitter 1.3 Data Buffers The ST-20 has 8 internal data buffers. Before a data buffer can be used, a valid Argos ID number, repetition rate and frequency must be assigned to the buffer. The Argos ID numbers must be entered as a decimal and a Hexadecimal number. The ST-20 uses the Hexadecimal format to determine if the ID is a 28 bit ID number. When using 28 bit ID numbers, 31 bytes of data can be stored in the buffer.
ST-20 Argos Satellite Transmitter 2.1.1 Result Code Result Code used to determine if command executed successfully. The Result Code is set true on success, and false on failure. 2.1.2 Buffer Number Buffer Number is the ST-20 buffer to setup. Valid entries are 0 through 6. 2.1.3 Decimal ID Number The Decimal ID number, and Hexadecimal ID are assigned to the Buffer Number. Entries must be valid ID numbers or ArgosSetup will return False.
ST-20 Argos Satellite Transmitter 2.2.5 NumRecords NumRecords is the number of data records that will be copied from the data table to the Argos PTT. Care should be taken to make sure the total amount of data does not exceed what the buffer can hold, 32 bytes for a 20 bit ID number and 31 bytes for a 28 bit ID number. See DataFormat (section 2.2.6) for details on regarding memory usage. 2.2.6 DataFormat There are two data formats.
ST-20 Argos Satellite Transmitter The ArgosDataRepeat instruction is most useful when only using 1 ID number because time between each buffer transmission is the rep rate. When using several ID numbers for each platform, the ArgosTransmit instruction allows the datalogger to control the timing of each transmission. If a buffer is set to transmit, but the buffer has not been setup with valid parameters, ArgosDataRepeat will fail. 2.4 ArgosTransmit Usage: ArgosTransmit(Result Code, Buffer Number) 2.4.
ST-20 Argos Satellite Transmitter directional and unity gain. The antenna should be mounted vertically. An antenna with gain will perform significantly worse then an antenna with unity gain. 3.2 Environmental Enclosure The ST-20 is designed to work in a dry, non-condensing environment. A proper enclosure should be used to keep water, dust and other environmental contaminates away from the ST-20. Always use desiccant inside the enclosure to keep trapped moisture from condensing on the electronics. 4.
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Campbell Scientific Companies Campbell Scientific, Inc. (CSI) 815 West 1800 North Logan, Utah 84321 UNITED STATES www.campbellsci.com info@campbellsci.com Campbell Scientific Africa Pty. Ltd. (CSAf) PO Box 2450 Somerset West 7129 SOUTH AFRICA www.csafrica.co.za cleroux@csafrica.co.za Campbell Scientific Australia Pty. Ltd. (CSA) PO Box 444 Thuringowa Central QLD 4812 AUSTRALIA www.campbellsci.com.au info@campbellsci.com.au Campbell Scientific do Brazil Ltda.
