In the past the high range mode wouldn't let you input a shunt greater than 0.99mOhm, but in this firmware I let it so that you could still go up to 9.99 mOhm in high range, but if you then switch to low range it will treat that as 99.9 mOhm and you won't see the first digit. I'll put some proper clamps on the input shunt ranges again so that you can't do this. Main thing to keep in mind is that the Range selection effects much more than just the display (W or kW, and .01A or 0.1A), it determines the entire internal scaling factor used for all the power related variables (ie signed 16 bits = +-32,000, could be seen as +- 320 amps or +- 3200 amps).
This functionality is still a bit... off.
Yep. I finally had an opportunity to flash v3B21, having been running with v3B19 because of the jerky starts unique to v3B20. I tried a few experiments setting RShunt in High Range mode and it does look a bit broken. I may be wrong, but it seems tied to the display and data entry functionality - the actual run time calculations seem to work okay if you can get the proper RShunt value set.
- In High Range mode there is a discrepancy between the displayed RShunt parameter value and the displayed value on the Calibration section summary screen.
- As mentioned in an earlier post, the RShunt data entry format in High Range (xxxx) seems a step back from the v3B19 format (x.xxxx). The exact position of the decimal point is unclear. By experiment, it turns out that it's to the left of the entry field (.xxxx), that is, 0.9999 = 9999.
- The High Range data entry field (.xxxx) cannot accept input of RShunt values 1.000 or greater since there is no available units digit.
- The last digit of the High Range entry field does not (in general) allow entry of an arbitrary digit [0-9] but instead jumps to some new digit as soon as the field is closed and stored (e.g. entering 4030 saves and displays as 4033).
There are some other observed quirks, but in the present context of attempting to enter RShunt = 1.xxxx in High Range, (3) above presents a bit of a showstopper...
As Justin cautions, this Low/High Range setting is really designed to be a one-time affair, and as MCiii reported, some odd things appear to permanently corrupt the (displayed) RShunt value when swapping from High Range back to Low Range. Since this is an official no-no, it's not really a shortfall, but...
As a work-around, I flashed v3B19 and configured the Range to High and entered my desired RShunt value of 1.403 mOhm. I then flashed v3B21 and immediately adjusted it for High Range so the preserved RShunt value would be properly interpreted. (The Range setting is not a Calibration parameter and is reset to Low when flashed). The RShunt value was displayed correctly on the Calibration section screen (1.40) although the RShunt Setup screen showed 4033 instead (missing the leading "1." and with the puzzling trailing "3"). I was careful not to try to alter this value with v3B21
. Going back to the start of Setup, I configured Setup normally, noting in particular that the default Max Amps and Max Power parameters had scaled up by x10
It was dark and rainy outside so no test run, but a run on the stand showed the main screen Watts display in kW with what appeared to be proper wattage readings. The set-in-B19-run-in-B21 gimmick seems to work and might be worth a try if you need this sort of RShunt setting plus presets - otherwise a downdate to v3B19 should do the job if the presets aren't really needed yet...