KEPCO BHK-MG 40W (Half Rack) Series - Manual (Page 76)

3-32
BHK-1/2-MG 121313
For each circuit, the digital programming section provides a voltage (DP (V) for voltage, DP (C)
for current), between zero and -10V d-c, applied to the input of a summing amplifier. This ampli-
fier drives, in turn, the voltage error amplifier and the pass element to produce the output. Each
circuit also includes an uncommitted amplifier which can be configured to be summed with the
output of the digital programming section at the input of the summing amplifier. Configuration of
the uncommitted amplifiers is accomplished at the ANALOG PROGRAMMING TERMINALS at
the rear panel: VOLTAGE PROG. terminal strip TB2 for voltage, CURRENT PROG. terminal
strip TB3 for current.
If digital programming is at zero, analog programming requires a voltage between zero and –
10V d-c to be applied to terminal 9 (TB2 for voltage, TB3 for current). If digital programming is
combined with analog programming, the voltage range for the signal applied to terminal 9 is:
Voltage programming: TB2-9: 0 to
Current programming: TB3-9: 0 to
where:
Eout
dp
= digitally programmed output voltage/voltage limit
Iout
dp
= digitally programmed output current/current limit
The uncommitted amplifiers can be configured to produce the required voltage from a number of
analog sources. Some basic analog configurations are presented in the following paragraphs:
• External resistance
• Low impedance voltage source
• Grounded voltage source
• High impedance voltage source
• Current source
Different analog sources can be used simultaneously; e.g., resistance can be sued to control
voltage programming while a grounded voltage source controls current programming. Analog
programming can also be combined with digital programming (either locally via the keypad or
remotely via the GPIB bus) since the two programming methods are summed together. For
example, for the BHK 500-80MG Power Supply, if the output is programmed digitally to 200V,
and an analog signal which would produce a 100V output is applied to the uncommitted ampli-
fied, the output would go to 300V (assuming the value of the load and the programmed value of
output current allow the power supply to remain in voltage mode).
NOTE: It is important to remember that BOTH voltage and current channels must be pro-
grammed (e.g., if analog programming of voltage mode is used, the current limit must
be programmed by either analog or digital programming).
The availability of the two uncommitted amplifiers, ±10V d-c reference voltages and the two
summing amplifiers, means that many configurations are possible for analog control of the
power supply.
10 E o u tdp –
10
E o m a x
---------------------- ×
 
 
V –
10 I o u tdp –
10
I o m a x
-------------------- ×
 
 
V –