The DAS is the LBA Data Acquisition System. At Mt. Pleasant, it refers to both the hardware (contained in beige panels beneath the frequency translator in rack 6) and the computer program that controls it.
Using the DAS Software
The DAS software runs on a Windows PC running in rack 9. You can also access this via VNC at
the progrm is controlled through the keyboard. Each page shows the possible commands along the lower edge of the screen, with the relevant key bracketed with < and >. If the DAS program is not running, you can restart it from the shortcut on the desktop (circled in red). If so, you will be asked to select a profile - you must choose
The current profile is listed in the upper left corner of the program (COR16000.PRO in the image above). If you need to load a different profile, press
Once it is loaded, you need to set up the hardware - press
Once you have the correct profile loaded and set up, you need to make sure that the IF power levels are correct.
The red loop shows the IF power level for channel 1 of the DAS and green is channel 2. The highlighted box shows the current power reading and C indicates the current target. In both channels, the IF power level is slightly higher than nominal. To centre the DAS, you should adjust the attenuation on the configurable backend to get the levels centred. Small changes in the power level (of 1–2 divisions on the DAS sliding scale) are normally seen when the telescope goes to different elevations and will be handled correctly by the DAS. The BSB and LSB sliding scales should be ok once the IF power level is correct.
The DAS monitors itself continuously and if alarms are enabled, it will produce an audible alarm when it detects a problem. The current status of the DAS is listed inthe yellow loop in the image above. If the alarms are listed as ON, there will be a loud alarm chime at Mt Pleasant if there are any detected problems. The usual cause is that the power levels have gone out of range (i.e the highlighted box on the slider has gone to the far end of the scale) or that there’s a problem with the electronics - check for any ERRORS in the yellow-looped area.