Solar Radiation Detector Readings

I am using owfs to monitor a Solar Radiation Detector (SKU S3-R1-A) through a 4-channel hub.  Other posts recommend using the 'vis' value as a measure of how intense the sun is.  owfs also reports S3-R1-A/current, S3-R1-A/gain and S3-R1-A/illuminance values.  What are these used for?
 
Thanks, Norbert

Unfortunately I am not an expert on all the values in owfs so your best bet for the best answer is to ask on their mailing list https://lists.sourceforge.net/lists/listinfo/owfs-developers

@ericvic, thanks for the pointer.  It looks like the values are different ways of representing the same data as 'vis'.  I will post data once I get a good run.

I finally got the various pieces working and collecting live data.  S3-R1-A/current appears to be the key value, measuring the photodiode output in micro-amperes.  The vis value is the voltage drop in volts when the current passes through a 390 ohm resistor (vis = current * 0.00039).  S3-R1-A/illuminance represents a lux value and is calculated from the current * S3-R1-A/gain (defaults to 105.263 assuming an SFH203P Osram photo-diode). 
 
Not having an accurate lux meter, I have no idea what the right gain value should be.  I was getting illuminance values ranging from 3000 to 9000 around noon today under varying cloud cover, which seems a bit on the low side.