KEPCO BOP 5-20DL, Operator'S Manual

Page: 37 / 70

BOP 5-20DL 081915
3-3
3.2.1 EXTERNAL PROGRAMMING RESISTORS.
External programming resistors should be high-quality units, with low-temperature coefficients.
Resistors should be selected carefully, since in most applications, the limitations for stability and
drift are due not to the BOP, but to the programming resistors. Selection criteria for resistors are:
• Temperature coefficient
• Leakage (in values above 100k ohm)
• Humidity effects
• Drift with time
• Self-heating (power dissipation)
• Tolerance.
For variable resistors (potentiometers or rheostats) similar selection criteria apply. In addition,
such specifications as listed below should be carefully considered if the application requires:
• End resistance
• Linearity
• Capacitive and inductive effects
3.2.2 ACTIVE PROGRAMMING SOURCES
External programming sources (Signal Generators, etc.) or reference sources should have tem-
perature coefficients and drift specifications comparable to (or better than) the BOP Power Sup-
ply.
CAUTION: A-C source-operated programming sources must have their output isolated
from the case.
3.2.3 EXTERNAL LEADS
Shielded (preferably twisted) lead pairs are recommended for all input connections to the BOP
control channels. The shield should be connected (single-ended) to the chosen signal ground
point. Shielded leads should be held as short as practicable. Output leads must be voltage-rated
for at least the maximum BOP output voltage and current.
3.2.4 EXTERNAL VOLTAGE MONITOR
Use signal E
O
Monitor Output at pin 20 of the Rear Programming Connector (see Figure 3-1 for
external voltage monitoring. Caution should be exercised in handling this signal: use a series 5K
resistor in combination with a high impedance monitoring device, or an external high impedance
buffer between the BOP and the monitoring device. This signal is buffered by an op-amp which
functions as a repeater for the signal coming from a matched pair divider connected at the out-
put. There is no overvoltage protection. This stage is protected against short-circuit by the intrin-
sic protection of the op-amp generating this signal. This signal is used by the BIT card if it is
installed.
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