Remote Voltage Programming, Non-Unity Gain (Constant Voltage); Remote Resistance Programming (Constant Current) - HP 6269B Operator’s, Organizational, Direct Support And General Support Maintenance Manua L

TM 11-6625-2958-14&P
Figure 3-5. Remote Voltage Programming,
Non-Unity Gain (Constant Voltage)
(less than 30ppm Per degree Centigrade) character-
istics in order to maintain the Supply's temperature
and stability specifications. Reference resistor R
should not exceed 10K. Note that it is possible to
use the front panel voltage control already in the
supply (A5R121) as the voltage gain control (Rp) by
simply removing the external Rp and strapping ter-
minals Al and A2 together.
3-31 The output voltage of the supply may be ad-
justed to exactly zero when the external program-
ming voltage is zero by either inserting and adjust-
ing R111 as discussed in Paragraph 5-84, or, if the
instrument is equipped with Option 020, by adjust-
ing potentiometer R112 as discussed in Paragraph
5-86.
3-32 REMOTE PROGRAMMING, CONSTANT
CURRENT
3-33 Either a resistance or a voltage source can
be used to control the constant current output of
the supply. The CURRENT controls on the front
panel are automatically disabled in the following
procedures.
3-34 Resistance Programming (Figure 3-6).
mode, the output current varies at a rate determined
by the programming coefficient as follows:
Model Programming Coefficient
6259B
6260B
6261B
6268B
6269B
The programming coefficient is determined by the
constant current programming current which is ad-
justed to within 10% of 2.5mA at the factory. If
greater programming accuracy is required, it may
be achieved by either adjusting R30 as discussed
in Paragraph 5-97, or, if the instrument is equipped
In this
4 ohms/ampere
2 ohms/ampere
4 ohms/ampere
6 ohms/ampere
4 ohms/ampere
Figure 3-6. Remote Resistance Programming
with Option 021, by adjusting potentiometer R116
as discussed in Paragraph 5-98. The output current
of the supply when zero ohms is placed across the
programming terminals may be set to exactly zero
by either inserting and adjusting R117 as discussed
R
in Paragraph 5-92, or, if the instrument is equipped
with Option 021, by adjusting potentiometer R119
as discussed in Paragraph 5-94.
3-35 Use stable, low noise, low temperature co-
efficient (less than 30ppm/°C) programming resis-
tors to maintain the power supply temperature coef-
ficient and stability s pacifications. A switch may
be used to set discrete values of output current. A
make-before-break type of switch should be used
since the output current will exceed the maximum
rating of the power supply if the switch contacts
open during the switching interval.
C A
If the programming terminals (A4 and
A 6) should open at any time during the
remote resistance programming mode,
the output current will rise to a value
that may damage the power supply
and/or the load. If, in the particular
programming configuration in use,
there is a chance that the terminals
might become open, it is suggested
that a 200 ohm resistor be connected
across the programming terminals.
Like the programming resistor, this
resistor should be a low noise, low
temperature coefficient type. Not e
that when this resistor is used, the
resistance value actually programming
the supply is the parallel combination
of the remote programming resistance
and the resistor across the program-
ming terminals.
3-4
(Constant Current)
U T I O N