KEPCO BHK-MG 40W (Half Rack) Series - Manual (Page 80)

3-36
BHK-1/2-MG 121313
FIGURE 3-10. ANALOG PROGRAMMING OF OUTPUT CURRENT (CURRENT MODE)
OR CURRENT LIMIT (VOLTAGE MODE) USING RESISTANCE
3.8.2.1 VOLTAGE MODE
With the power supply in voltage mode (see Figure 3-9) and the digitally programmed output
voltage at zero, varying the external resistor from 0 to 10K causes the output voltage of the
power supply to vary linearly from 0 to E
O
max with a slope of (0.0001 x E
O
max) volts per ohm.
The following equation gives the output voltage as determined by external resistance R
EXT
.
Eo = (–1) (10V) x (R
EXT
/10K) x (–1) (10K/10K) x (–1) (R/10K)
= (–1) (0.1 x R) x R
EXT
= –0.1R x R
EXT
(V d-c)
where
R
EXT
= External resistance (K-ohms), variable from 0 to 10K ohms. This resistance can take
the form of a rheostat, a fixed resistor, or a group of resistors which are step-switched
by mechanical, electrical or electronic means (step-switching must be “make before
break”). Use only high quality resistor(s) having a temperature coefficient of 20 parts
per million or better and a wattage rating of 0.5W minimum.
R = Internal feedback resistance (K-ohms), determined by Model (see Table 3-10).