Geodynamics GPS Fieldwork

The Australian National University
Research School of Earth Sciences
Geodynamics Group

Quirks of the DSCC

Written by Paul Tregoning pault@rses.anu.edu.au

Hardware

The DSCC at present is a PC-104 card with a TB486 processor board. This means, a 486sx style computer without a math co-processor (and without much grunt!). The advantages of this processor are that it has 3 serial ports (which we need) and low power consumption.

The disadvantages are that without a math co-processor it takes time to run programs. It can also be difficult to acquire proprietry software that is compiled with co-processor emulation.

One possibility to overcome this is to use a more powerful PC-104 computer. It will draw more power but would probably run for less time (hence a power saving?).
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Software

The operation of the DSCC is entirely up to you. At RSES we have always considered that the PCON operation was the responsibility of Norm Schram (the electronics wizard) and that the DSCC operation was the responsibility of Paul Tregoning (the end user). We end users have provided feedback into the development of the PCON firmware but we cannot change it directly.

The DSCC software is our domain and entirely our responsibility. Here you can decide:

when/whether to turn on the satellite phone (and who and how to call!)
what criteria should be used to bring the system out of hibernation
what alarm time the PCON should have set
how to download the GPS data
whether or not to download/read/use/store the PCON diagnostic data

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Known Problems

The only known problem with the DSCCs is that, for reasons not yet understood, they sometimes lose their BIOS settings during the winter. This is probably caused by either low battery voltage or cold (or both); however, we have data which can disprove either case - that is, we have operated a DSCC at low battery voltages without corrupting the BIOS (where other cases it has died) and also at -25 deg C (where in other cases it has died at higher temperatures).
The ramifications of this fault are very serious. The default settings of the DSCC are that the IDE adaptor (the flashcard connector) is DISABLED. Since this is where the operating system resides, the DSCC won't boot until it has its BIOS setting changed - that is, human intervention is required.
Without a functioning DSCC, the PCON diagnostic data will not be stored (the PCON has a FIFO memory system and will store only two days of data). Furthermore, the system will not wake from hibernation until 15 October, whereas a functioning DSCC may have decided that there was enough power available to start operations in September. Also, once the GPS receiver is operating it won't have its data downloaded and deleted. Therefore, it will simply record until it fills and then stop recording - after about 2 weeks.
Solution: We don't actually have one at this stage - primarily because we haven't isolated the cause of the problem. Having had two additional DSCCs fail in this manner in 2001 we now MUST fix this problem for the 2002/03 deployment. There is a possible fix in that we can configure the DSCCs to read a default BIOS setting from an EEPROM - RSES Electronics are looking into this. If it works it should solve the problem.

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Last modified:2002 March 18 pault@rses.anu.edu.au