FAQs and Common Problems

The Multi-PIP comes with 3 modes by default: Default, Low, and High. Each mode allows the Multi-PIP to measure a different impedance range.

1. Default mode can measure in the impedance range of 14 KΩ to 5 MΩ.·

2. Low mode can measure in the impedance range of 500 Ω to 20 KΩ.

3. High mode can measure in the impedance range of 500 KΩ to 50 MΩ.

For most plant tissue, Default mode will most likely suffice. For users who are just getting started, we recommend using Default mode to avoid confusion.

For more experienced users, we recommend selecting a mode on a probe by probe basis depending on the expected impedance values of each probe.

Is there a limit to the impedances the Multi-PIP can measure?

For high impedances, the accuracy of the Multi-PIP is frequency dependent.

1. For frequencies above 50,000 Hz, the upper limit on measurable impedance is ~7.5 MΩ. Thus, any impedance measured 7.5 MΩ and above will result in the same value.

2. For frequencies below 50,000 Hz, the upper limit on measurable impedance will increase as frequency decreases. For example, at 100 Hz the instrument may measure impedance values in the 100s of MΩ. However, extraordinarily high impedance values should be taken with a grain of salt, as the instrument is not calibrated (see above details on modes) to measure anything above 50 MΩ.

Are the Multi-PIP’s impedance measurements effected by temperature?

In the 0-60 C temperature range, temperature does not affect the impedance values measured by the Multi-PIP. Any variations in impedance will be associated with the plant and its internal conductivity.

Outside of the 0-60 C range, the instrument might have trouble operating due to the battery, but any measurements it takes will still be accurate.

Why do phase measurement values vary for different frequencies?

As of the writing of this article, measured phase values are uncalibrated for different frequencies. However, for a particular frequency, phase is constant for measuring any arbitrary resistor value in any device measurement mode on any channel, so long as the resistor is in range of the measurement mode.

Phase should be calibrated in post-processing with a generated calibration using the following two easy steps:

1. Measure a resistor that is within the range of the measurement modes at the frequencies of interest with your instrument.

2. Offset any future phase for a particular frequency measurement using the phase values generated in (1).

What is the battery life on the Multi-PIP?

Expected Battery Life

For most device configurations, we expect a full device charge to last ~3 weeks. This duration can vary dramatically depending on the following :

1. Number of frequency measurements being taken.

2. Number of probes being measured.

3. Measurement interval.

4. Ambient temperature.

Common Problems with Battery Life

If your Multi-PIP is losing more than 20% battery over a short period of time, please check the following:

1. Ensure that the Multi-PIP is not plugged into an unregulated power source.
   Hooking up the Multi-PIP to an unregulated solar panel or battery pack can result in rapid draining of the battery.

2. Ensure that the Multi-PIP is going to sleep between scheduled measurements.
   After beginning scheduled measurements, ensure that the device goes to sleep by pressing the power button on the device. The LED screen should shut itself either immediately, or when a measurement actively being taken is complete.

Does the Multi-PIP wound plants?

Yes, after probes are first connected to the plant, there is generally a "wounding signal" visible in the impedance. Generally, this signal begins at low impedance magnitudes and increases steadily over the course of a few hours. During this time, regular diurnal cycles are unlikely to be present in data.

While the duration of the "wounding signal" is usually short , we recommend waiting for regular diurnal cycles to establish themselves in the data prior to beginning to interpret Multi-PIP data.