I am planning to use a Garmin GPS16X-HVS in a CR3000 weather station which is powered with a SP20 solar panel. In the interest of conserving power, can the Garmin be powered up and down by using a control port? The power switch line (yellow), according to the Campbell Scientific documentation, is to be tied to ground (<0.3 V) during operation. Does this mean that if the yellow line was tied to a control port, this port could power the GPS on and off? If not, I suppose I could use one of the SW12V ports.
I have never used a GPS16X-HVS but from looking at the manual I don't think you are suppose to tie the yellow wire (power control) to a control port to turn the unit on and off.
As near as I can tell from the manual when the yellow wire is not connected to anything (open circuit) the unit is off. When the yellow wire is connected to ground the unit is on.
Instead of using the switched 12V to turn the unit on and off, you could use a 12V relay from RadioShack to connect the yellow wire to ground. When the switched 12V is on the relay is closed connecting the yellow wire to ground on the datalogger.
Alternately, if you wanted to use a control port you could build a relay driver (fig. 48, p. 97 in CR1000 manual). I have built many of these relay drivers back in the days before switched 12V was available on the datalogger. They are easy to build, parts are cheap and readily available at RadioShack.