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Rpv
VALUE
6826A
6827A
HIGH
RANGE
LOW
RANGE
HIGH
RANGE
LOW
RANGE
0
-51.2V
-5.12V
-102.4V
-10.24V
10.24KO
OV
OV
OV
OV
20.48 KH
+51.2V
+5.12V
+ 102.4V
+ 10.24V
3-44
As noted above, the output voltage should be zero
volts with 10.24K connected to the programming terminals.
The output may be adjusted to zero by adjusting the V
ZERO ADJ potentiometer as described in Paragraph 5-104.
The output voltage varies from the maximum negative value
to the maximum positive value through 0 at a rate deter¬
mined by the resistance programming coefficient as follows:
MODEL
* PROGRAMMING COEFFICIENT
HIGH RANGE
LOW RANGE
6826A
6827A
200 ohms/volt ± .1%
100 ohms/volt + .1%
2000 ohms/volt ± .1%
1000 ohms/volt ± .1%
* Precision programming resistors (±0,05%) must be used.
--CAUTION--
When remote control programming is employed,
the FLAG (A 17) and REMOTE RANGE (A 11)
programming connections must be isolated from
the computer ground.
3-45
The switch connected between the A11 and -S
terminals allows remote selection of the high (X10) or low
(XI) range. Note that the front panel RANGE switch must
be in the REMOTE position in order to utilize the remote
selection feature. The remote dc control voltage connect¬
ions between terminals A15 and A16 activate an internal
relay. When the control voltage is applied, the internal re¬
lay is energized momentarily disabling the input driver to
the BPS/A error amplifier. This feature is used to prevent
transients from affecting the output when the programming
input is changed. Terminal A17 provides an indication to
the external programming device when the BPS/A is in con¬
stant current operation.
3-46
Variable Gain Amplifier. For variable gain amplifier
operation, an external input signal (dc to 15kHz), applied to
terminals A1 (HI IN) and A2 (LO IN), is amplified or atten¬
uated. The gain is variable from 0 to a maximum value as
the value of Rpy varies from 0 to 20.48K ohms. The variable
gain at the high and low ranges is as follows:
MODEL
VARIABLE GAIN
HIGH RANGE
LOW RANGE
6826A
0-20
0-2
6827A
0-40
0-4
-CAUTION-
The voltage applied to the input terminals, HI IN
(A1) and LO IN (A2), must not exceed 50 V
(maximum) or the instrument may be damaged.
3-47
Resistance Programming, Constant Current. Pro¬
gramming resistors
(Rpc),
connected as shown in Figure
3-6, can be used to control the constant current output.
The front panel CURRENT control is disconnected (disabled)
when the remote
Rpc
resistors are connected as indicated.
Resistance programming of the constant current output
can be accomplished in all three modes of operation (power
supply, variable gain amplifier, and fixed gain amplifier).
Individual Rpc resistors control positive and negative con¬
stant current outputs respectively. The positive or negative
output current is variable at a rate determined by the pro¬
gramming coefficient as follows:
MODEL
OUTPUT
CURRENT
* PROGRAMMING
COEFFICIENT
6826A
6827A
Oto 1.024A
Oto .512A
10 ohms/mA ± .1%
10 ohms/mA ± .1%
* Precision programming resistors (±0.05%) must be used.
--CAUTION-
A load must be maintained at all times during
constant current operation. The load can be a
WOK El resistor for the 6826A or a 400K LI
resistor for the 6827A.
3-48
Zero output current for zero programming resis¬
tance can be assured through proper adjustment of the front
panel +1 and —I ZERO ADJ potentiometers (see Paragraph
5-107).
3-49
Voltage Programming, Constant Voltage. Voltage
programming of the output voltage can be accomplished in
the variable gain or fixed gain amplifier mode of operation.
Voitage programming is not applicable in the power supply
mode.
3-7
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