Sapflow Troubleshooting

[stephpenn1]

See #1 for download protocol. Open files and scroll through, expected values should be between 0 and 1.

If you see NANs or negative numbers ... things to check:

• main power supply: are there nicks in the cable?
• wiring in datalogger: is the light on on the power regulator?
• go to the tree where the signal is bad, check cable there for nicks
• terminal and wire connections at the sensor
• are the needles in the tree bent, broken, chewed?

If you find the issue and it seems fixable (i.e. power is out, miswired, or bent) try fixing those before replacing sensor. Replacing a sensor should be the last option as it requires drilling a new hole and tons of extra work, supplies, etc..

Replacing a sensor:

Items needed:

• sensor
• tube pusher, brass tubes, grease
• drill
• small screwdriver

Protocol:

• remove bad sensor from tree and disconnect from terminal block, brass tube casings are too difficult to remove to don't worry about those
• drill new holes, insert brass casings using tube pusher
• coat new sensor needles in heat-conductive grease, insert into tree and reconnect cable endings to terminal
• check sensor signal on laptop before wrapping bag on terminal block and taping