Control / Limits
7300A User Manual
4-4
4.2.2. CURRENT AND POWER LIMITATION
With the contol option VICL, the following are available:
• ‘I lim’ current calibration potentiometer
• ‘VI lim’ power calibration potentiometer
• HRC calibration control signal on the ‘ADJ.CAL’ terminal block
Recalibration is possible:
• current I
max
from 20% to 100% of I
N
• power P
max
from 50% to 100% of (V
N
. I
max
).
The HRC setting control signal (‘ADJ.CAL’ terminal block) can be used to aid setting with
the ‘I lim’ and ‘VI lim’ potentiometers whether or not the thyristor unit is firing.
Setting current and power limitation
The value of the DC voltage between terminals HRC (67) and 0VC (66) represents:
• The image of the maximum current (‘VI lim’ potentiometer fully turned in the
direction of the arrow)
• The image of the maximum recalibrated power (1 V corresponds to 100% P
N
).
The control signal is equal to 1 V if calibrations are nominal (I
max
= I
N
and P
max
= P
N
).
The minimum value of the signal is 0.1 V (I
max
= 20% and ‘VI lim’ set to 50% of V
N
. I
max
).
Setting:
1. Turn the ‘VI lim’ potentiometer fully round in the
direction of the arrow (nominal power).
2. Use the ‘I lim’ potentiometer to set the I
max
value.
3. Use the ‘VI lim’ potentiometer to set the P
max
value.
Check the resulting power setting on the HRC signal
(accounting for I
max
) .
Important:
The current limitation must be done before adjusting the power limitation.
ADJ.CAL 66 0VC 67 HRC
ANA
31 0V
A
32 RI 33 5V
A
V
