KEPCO MBT Series - Manual (Page 49)

MBTSVC111609
3-11
3.2.1.6 SETTING OUTPUT VOLTAGE OR VOLTAGE LIMIT
There are three ways to set output voltage or voltage limit: 1) Vadj and numeric keys, 2) slew
keys, and 3) the VOLTAGE control. The display should be reading either “Output is off” if
the output is disabled, or “Keypad control” if the output is enabled.
3.2.1.6.1 USING VADJ AND NUMERIC KEYS — M, MG MODELS
The Vadj and numeric keys can be used to adjust either output voltage or voltage limit (either
the actual value or the programmed value). The effect of the numeric keypad entries is depen-
dent upon the model, the previously commanded mode, whether the output is enabled or dis-
abled, and the load value.
For M and MG models, when the output is disabled, the output voltage and current are pro-
grammed to zero, and the power supply remains in actual voltage mode. If the output is
enabled, the power supply will operate in voltage mode except for the case where the value of
the load is less than the programmed voltage divided by the programmed current (R
L
< V
Prog
/
I
Prog
). In this case the MBT power supply will be forced into Current mode.
Table 3-3 summarizes the effect of the Vadj adjustment. The first three columns reflect the sta-
tus of the unit before the Vadj command is issued. The fourth column shows the message on
the front panel display after the Vadj is pressed and the fifth column shows how the adjustment
will affect the status of the power supply. Refer to PAR.s 3.1.1 and 3.1.2 for more details regard-
ing commanded and actual mode of operation (either voltage or current).
If the output is enabled and the value of the load is greater than or equal to the value of pro-
grammed voltage divided by programmed current (R
L
≥ V
Prog
/ I
Prog
), the power supply oper-
ates in voltage mode and the keypad entries adjust actual output voltage, contrary to the display
indication.
If the output is enabled and the value of the load is less than the value of programmed voltage
divided by programmed current (R
L
< V
Prog
/ I
Prog
), the power supply is forced to operate in cur-
rent mode and the keypad entries adjust actual voltage limit.
If the power supply was operating in a remote configuration, setting output voltage or voltage
limit can also be influenced by the last command issued to the power supply before the unit is
put into Local Mode. If the power supply was commanded to operate in Current mode before
being set into Local mode, Table 3-3 indicates that if the load allows the power supply to operate
in voltage mode, Vadj and the keypad entries adjust either actual output voltage or programmed
voltage limit, depending on whether the load is enabled or disabled. If the load forces the power
supply to operate in current mode, Vadj and keypad entries will adjust actual voltage limit, con-
trary to the display indication.
Refer to PAR. 3.2.1.6.3 for procedure.