Alignment of high-frequency data

[patricktokeeffe]

The high-frequency instruments all have different inherent delays which must be accounted when aligning time-series data for flux computations.

Sensor	Delay (ms)	Ref
CSAT3 (level B1)	2 scans = 0.2 sec (using command 98 & group trigger ✓)	CR1000X.Std.05.00 CRBasic Help & CSAT3B User Manual rev 3/18
CSAT3B (all others)	1 scan = 0.1 sec (using mode 0 ✓)	CSAT3B User Manual rev 3/18
LI-7500 (levels B3 & D4)	fixed 186ms + user-configured delay (unknown*) recommended delay step is 17 to yield total delay of 297ms	LI-7500 User Manual Rev 4 (2004)
LI-7500A/RS (all others)	fixed 130ms + user-configured delay (unknown**) recommended delay step is 25 to yield total delay of 297ms	LI-7500A/RS User Manual rev Oct 13, 2021

*need to verify, might be set to 17 already from prior use
**need to verify, not sure if these were ever changed

[patricktokeeffe]

@zmgao did you update SDM delay steps for any of the LI-7500A/RS? I only had time to connect to the D2 IRGA last week and I recall seeing user-defined delay was still 0