[sdiy] DG413 question

[JH.]

>>V+ = VL = 30V
>
>And?  V- = GND = 0V ?

Well yes; actually I have V+ = VL = +15V, and V- = "GND"-Pin = -15V, but 
that's equivalent to single supply 30V with VL = V+.

>Where does the logic threshold turn out when you do  it this way?

It's unspecified - which made me wonder if that mode is allowed at all - but 
now that the latter is sorted out, I'm happy with _any_ threshold 
between -14V and +14V, because I use pull-down resistors to -15V, and the 
rotary switch wiper at +15V. The various OR'ed states (like, a switch being 
on at positions 2 and 3) are made with diodes and another pulldown resistor.

I would never use this for anything that needs any decent measure of 
_speed_ - but I'm just switching manually, at a lot of different points in 
the circuit.

JH.