Vo = mRpot + Voff, Rpot in ohms, m in Volts/Ohm, so at 0 ohms (assuming you have the 27V supply)
so Voff at 0 ohms = .7 x 27 volts = 18.9V
@ 1.8K ohms
(.9)(27) = m1800 + Voff = 1800m + 18.9 = 24.3
So m = (24.3 – 18.9) / 1800 = .003
So we have Vout = .003 x Rpot + 18.9 or Rpot = (Vout – 18.9) /.003
So at 24V Rpot = (24 – 18.9) / .003 = 1700 ohms
So at 27V Rpot = (27 – 18.9) / .003 = 2700 ohms
So pot wants to range from 1700 ohms to 2700 ohms,.
So use a series R of 1700 ohms with 1000 ohms pot.
This is approximate because their graph shows linear behavior, except 100% out of supply is
infinite R which is not linear with the graph.
Regards, Dana.