Are you sure about the history scaling? I think the history rainfall field is in bucket tips, with each tip being about 0.01", or 0.25mm.
It's been raining here for an half-hour or so: These are my data
Time Ptype Stype Value
19:09 2 10 6.19
19:05 2 10 4.9
19:01 2 10 4.38
19:00 9 10 0
18:58 2 10 4.12
18:57 2 10 3.87
18:53 2 10 3.35
18:49 2 10 2.58
18:45 2 10 2.32
18:45 9 10 0
18:42 2 10 2.32
18:41 2 10 2.06
18:30 9 10 0.01
18:21 2 10 0
18:17 2 10 0
18:15 9 10 0.01
18:13 2 10 0
18:09 2 10 0
18:05 2 10 0
18:01 2 10 0
17:49 2 10 0
17:45 2 10 0
Packet type 2 are SDPs, and type 9 are history values. All the sensor types are current rain hour on my system. The values are as reported by the weather station, no scaling except for the decimal points (i.e. whatever units they are, I not converting them to anything).
As you can see, the history packets were reporting something before the SDPs did. And while the SDP values continued to rise, the history values were 0's. I only see history values of 0, 1, 2 and 3 in my data, so clearly these are not bucket tips.
Update: until we can figure these out, I'm removing them from my datasets.
Update 2: I only see values 0, 1, and 2. There may have been history packets before I started saving them that had values of 3, but I can't prove that now.
Update 3: Based upon a review of the rainfall values I'm getting vs. the readings from a standard rain guage, I think a much closer interpretation of the rainfall values is that they are in thousandths of an inch.Update 4: Based upon a comparison of the current rain since reset value of 15.996 in the SDP vs. 0.62 in. on the display, it seems that that the rain values are indeed in units of 0.01mm.