Automatic Restart Function For the LI-8100A Automated Soil Flux System

The LI-8100A has the capability to restart a measurement following a power interruption to the instrument. Enabling this feature requires the user to first reposition a small jumper in the Analyzer Control Unit housing. When the jumper is repositioned, power will be restored to the instrument when it becomes available; note that this function is available only when the LI-8100A is powered via the Auxiliary Sensor Interface, and is not available when powered by a battery inside the Analyzer Control Unit. Note, too, that in order to restart the measurement, this feature must be also be enabled in software, following the jumper placement.

The LI-8100A jumper is located on the underside of the circuit board located directly below the PC card slots in the Analyzer Control Unit. Remove the access panel to view the jumper. Note that there are three pins aligned horizontally on the underside of the circuit board, below the words “Power On” imprinted on the circuit board. When configured at the factory, the jumper covers the leftmost and center pins (Keypad position, Figure 1‑1). In this position, if power is interrupted, the instrument can only be restarted by pressing the On/Off button on the keypad. By repositioning this jumper so that it covers the center and rightmost pins (Aux In position, Figure 1‑2), power can be automatically restored when it becomes available.

Figure 1‑1. Keypad jumper position.

IMPORTANT: When the jumper is in the Aux In position, the LI-8100A presents a potential shock hazard. For example, if power is interrupted and the unit shuts off, it is possible to remove the access panel and make contact with electrical components; if the user is unaware that a power interruption caused the instrument to shut down, power could be automatically restored while the user is in contact with these internal components. For this reason, we recommend that you always disconnect the power supply from the instrument before servicing any internal components in the Analyzer Control Unit.

Figure 1‑2. Aux in jumper position.

If you want the LI-8100 to restart the current measurement following a power interruption, reposition the jumper to the Aux In position as described above, and enable the Auto Restart function in software; in the LI-8100A Windows software, choose Instrument Settings from the 8100 menu and enable the ‘Resume measurement on instrument restart’ check box. In the LI-8100A Interface Software for Palm OS, tap on Instrument Settings on the 8100 menu, and enable ‘Automatic Restart’.