We have an FDSI (Field Diagnostics) Service Assistant Tool which uses a Palm Pilot which is Software Driven with a program that gives you complete information about a residential split system and can also be used for commercial systems (It was originally invented and first made for Commercial applications)
This manifold kit also comes with a wireless bluetooth kit which Measures Dry Bulb AND Wet Bulb Temperatures on Return Air AND Supply Air together as well as Cooper Atkins Clamp Temperature Probes for Suction and High Side Lines to measure Subcooling and Superheat. There is also an Outdoor Ambient Temperature Sensor with extension wire. This system guides you along and pretty much tells you where the trouble areas are on the system.... Airflow issues, Charging issues, etc. You DO need the Knowledge of refrigeration systems to use this and should know superheat and subcooling to properly diagnose what the machine/system is telling you per the instruments calculations and results.
If you are in Illinois, this machine/kit is used to pay incentives to you for each A/C clean and check (Tuneup) as well as 14+ SEER Installations (QIVs) from ComEd (Commonwealth Edison) This machine has over $9500 of incentives or more on it ready to be claimed via performing the jobs with this tool. A/C season is starting up very soon and this can make you extra money on each clean and check and installation. This Program for claiming incentives is actually run by ComEd AND Honeywell AND FDSI which pretty much all together support the instrument and help you whenever needed. We used this tool I believe under 15 times so it is still in Excellent to Near Mint Condition and goes for around $4200 Brand New and you can buy this one for ONLY $3200.
Like I said, please PM me for more details and pictures.