404 Considerations for Latitudes between 23 ½ N and 23 ½ S

Considerations for Latitudes between 23 ½ N and 23 ½ S

Calibration Considerations:

This pertains to to 2 Axis Versions 404 and above and not for Single Axis or Parabolic Trough .

These lower latitudes experience different paths of the Solar Azimuth which require the tracker to operate the entire 360 range of the compass. Between the equator and 23 ½ N, the sun will rise in the east and track to the south and set in the west for most of the year. This is called a southerly path.

Near the summer equinox, in June, the sun will rise in the east moving south and then track to the north. It crosses 0 degrees north to 359 degrees and eventually sets in the west. This is called a northerly path.

This means that the tracker will operate for most of the year as all other trackers in the northern hemisphere above 23 1/2 deg. N but will behave like on in the southern hemisphere for part of the year.

azimuth

When moving along the northerly path, it is important that the controller keeps track of how it arrives in the quadrant between 270 deg. and 360 deg. so it can return in the same direction  and not wrap wiring around damaging the assembly. This is why it is important never to start operating your tracker the first time in this quadrant by manually moving it via the northern path because it will return via the southern path unless configured to do otherwise.

Tech Note:

The Tracker IPm automatically defaults to expecting a southerly path. This is reflected in register AX117 SOLAR_PATH as 0. If you have positioned the tracker to 320 deg. N via the northern path, simply change the 0 to 1. The controller constantly monitors the solar path and keeps track of this in non-volatile memory. A power loss will not affect this.

Limit Switches

The wide range of travel in the lower latitudes creates specific considerations for minimum limit switch placement. Your minimum switch cannot be placed in the east because it will prevent the tracker from tracking via the northern path. It therefore has to be placed somewhere in the northwest quadrant, ie. 290 degrees.