KEPCO BHK-MG 40W (Half Rack) Series - Manual (Page 115)

BHK-MG 1/2 OPR 121313
4-3
NOTE: The message
Can’t Adj. Full Scale
is displayed if either a load less than nomi-
nal or a shunt resistor is connected to the output terminals during voltage calibration. If
this occurs, it is necessary to press ENTER followed by RESET to restore proper oper-
ation. Disconnect load or shunt and refer to PAR. 4.4, step 1 to restart calibration.
4.4.2 CURRENT CALIBRATION
1. LCD reads
CONNECT SHUNT zz A
(nn and zz values are determined by BHK-
MG model being calibrated.; e.g., for BHK 1000-40MG, LCD reads
<50 OHM >10 W
). (Refer
to PAR. 4.2 for shunt requirements.) Connect Precision Shunt across output terminals and
press ENTER.
2. LCD reads
CONNECT DVM TO SHUNT
. Connect DVM (+) input to sense terminal of shunt
connected to output (+), DVM (–) to sense terminal of shunt connected to output (–). Press
ENTER when connections are complete.
3. With LCD reading
I ZERO adj.
, monitor DVM and use or keys to increase or
decrease output current as necessary for minimum positive DVM reading. Press ENTER
when complete.
4. LCD will flash
I F.S.adj. **WAIT**
then
I F.S. adj < >
. Monitor DVM and use
or keys for fine adjustment and 3 or 1 keys for coarse adjustment to increase or decrease
output voltage as necessary to get V
DVM
reading as close as possible to value listed below.
Press ENTER when complete.
V
DVM
= Rs x Io
MAX
(mV)
where
Io
MAX
(mA) is the maximum value of output current:
BHK 300-130MG: 130mA
BHK 500-80MG: 80mA
BHK 1000-40MG: 40mA
BHK 2000-20MG: 20mA
Rs (Ohms) is the actual value of the external shunt resistor.
NOTE: The message
Can’t Adj. Full Scale
is displayed if either the shunt resistor is not
connected to the output terminals during current calibration or if the shunt resistance is
too high. If this occurs, it is necessary to press ENTER followed by RESET to restore
proper operation. Refer to PAR. 4.3, step 1 to restart calibration.
5. LCD will show
Curr 10X adj. Value = -.---mA
. Monitor DVM and convert V
DVM
to
mA as follows, then note the value of 10X current (milliAmps).
Io
10X
(mA) = V
DVM
(mV)/Rs
where
Io
10X
(milliAmps) is the enhanced value of output current in the first 10% of the range.
Rs (Ohms) is the actual value of the external shunt resistor (the same shunt resistor can be
used for Low scale, High scale and 10X current calibration).
6. Use the keypad to enter the value of Io
10X
(milliAmps) noted in step 5 and press ENTER. If
the value is out of range, (more than 10% of output current nominal value), the message dis-
plays 10% of the maximum output current for that model, e.g.
Imax=8.0000mA
for BHK
500-80MG. Press CLEAR twice to return to step 5.