LCR Driver Range Not Working

[amp-bjorn]

The range function in the LCR driver is not working. The issue is that we attempt to perform a fancy string to number to string coversion. The LCR will only take the following in its SCPI commands (tested manually)

📖 SCPI Command Reference

The driver wraps these low-level serial commands into high-level Python methods.

Command	Parameter Options	Description	Example Usage	Example Return (Blank means no return value)
*IDN?	-	Identity check	*IDN?	Agilent Technologies,U1732C,...
SYST:ERR?	-	Error queue check	SYST:ERR?	+0, "No error"
MODE	SER, PAL	Series vs Parallel	MODE SER	-
DISP2	D, Q, TH	Set secondary parameter	DISP2 Q	-
FREQ	100, 120, 1k, 10k	Test frequency (Hz)	FREQ 1k	-
FUNC	R, C, L, Z, ESR, AI	Primary measurement type	FUNC C	-
RANG	See Range Table below	Set manual range	RANG 20u	-
FETC?	-	Read primary value	FETC?	+6.856E-07
FETC? ALL	-	Read all parameters	FETC? ALL	Rs,+3.809052E-13,Ls,+4.316664E+09,Rp,+6.172276E-14,Lp,+4.316802E+09,Z,+4.316733E+09,TH,+5.774222E-01,F,+1.000000E+03,D,+1.774207E+02,Q,+5.636322E-03

📉 Range Options by Function

Function	Available Range Arguments
R / Z	2, 20, 200, 2k, 20k, 200k, 2M, 20M, 200M
L	2000u, 20m, 200m, 2, 20, 200, 2k
C	2000p, 20n, 200n, 2000n, 20u, 200u, 20m

source

[daniel-montanari]

In addition to this there are a few other drivers that use this
Keysight 33500b - turns fixed strings into numbers
rigol dg1022 - turns fixed strings into numbers
agilent u1732c (this driver) - turns arbitrary input into numbers (with bugs)

I think we should remove unit_scale entirely, fix up any scripts that rely on it, and delegate any sort of api related behaviour to drivers only, and force users to put numbers in, instead of strings with multiple formats.