On Tuesday the 19th, we removed the electronics package (the "brain") and retrieved the SAMI pCO2 sensor. Both were brought back to the lab for work that afternoon and evening. Also, Chris reports that he cleaned the underwater light sensors.
Back at the lab, Chris downloaded the stored data from the SAMI, and it appears as though the instrument has been worked properly since its deployment in November. The "brain" had the following work done:
- the RF400 was updated to the latest firmware and set to 38.4K baud (and radio communications were tested in the lab)
- the barometer, whose molex plug was broken during removal, was rewired directly to the datalogger ports
- the transmitter was replaced with a unit brought from Miami for this purpose
- the datalogger program was updated to communicate with the SAMI at 19.2K baud (instead of 9600 baud)
- all stored data was downloaded from the memory module
On Wednesday the 20th, we started by completely replacing the satellite antenna and its cable, then reinstalled the "brain" package. At the same time, Chris and Derek redeployed the SAMI and cleaned the CTDs.
In our first post-installation test the Deep BIC was offline due to its power (+12V) wire having come loose, so the station was re-opened to correct this problem. However, all other instruments (including the Groundtruth CT and the SAMI itself) were working okay. In subsequent tests, 100% of station instrumentation was found to be connected properly and reporting correctly.
Note: we observed a large bird "parked" on the surface light sensor for parts of Wednesday morning. We have one picture of this bird. There was also a lot of bird guano on the satellite antenna, which is the largest, highest and flattest part of the station.
Conclusions: the SAMI is now connected and its data is available on our web site. We conclude that there was never any cable or wiring problems with the SAMI and the reason it didn't report data after the November trip was the incorrect baud rate (the SAMI was set to 19.2K baud, the datalogger to 9600 baud). This problem was fixed by updating the datalogger baud rate to 19.2K for the SAMI since we didn't have the needed hardware to change the baud rate on the SAMI.
Also, initial performance of the replaced transmitter/cable/antenna was encouraging although since then we've seen evidence that the transmitter may still be dropping transmissions as before (see, e.g., records from the early hours of December 24th). Since the transmitter, cable and satellite antenna have all been replaced it seems possible that something external is interfering with transmissions. I'm going to ask CSI whether this could be caused by a bird perching on the antenna (!).
Also note that UPR will need us to send them more copper screens for the CTDs.
-- Mike J+