Section 4
OM7520-B-00
27 September, 2019
4-5
4.10.
MEASUREMENT CONFIGURATION E: 100 VOLT COMPARISON
Configuration E is used for comparison of a 100 volt source to a 10 volt reference standard
through the voltage divider set up for a 10:1 division. The Input Voltage terminals are
connected internally to the high side of the 7520 divider resistance chain input. The low
side of the divider chain produces 10:1 ratio of the 100 volt source (i.e. outputs 10 V) to be
compared with the 10 V reference voltage that is connected to the Reference Voltage
terminals. The comparison is done via an external null detector connected to the Null
Detector terminals.
4.11.
MEASUREMENT CONFIGURATION F: 1000 VOLT COMPARISON
Configuration F is used for comparison of a 1000 volt source to a 10 volt reference
standard through the voltage divider set up for a 100:1 division. The Input Voltage
terminals are connected internally to the high side of the 7520 divider resistance chain
input. The low side of the divider chain produces 100:1 ratio of the 1000 volt source (i.e.
outputs 10 V) to be compared with the 10 V reference voltage that is connected to the
Reference Voltage terminals. The comparison is done via an external null detector
connected to the Null Detector terminals.
4.12.
INTERNAL RATIO ALIGNMENT
The 7520 Precision Voltage Divider is designed with a fully automatic Voltage Ratio
Alignment function (i.e. Self Calibration) which can be invoked from the front panel touch
screen as may be desired by the user. The Voltage Ratio Alignment cannot be performed
when the 7520 is powered on until the temperature controlled chamber has come up to a
stable temperature. The alignment function is completed within 2 hours and the touch
screen will report the results of the alignment. There are no external components required
for the internal ratio alignment as the 7520 has an internal, very stable, Zener based
Voltage Reference source which is temperature controlled, an internal very low uncertainty
optical based Null Detector, and an internal Wheatstone Bridge.
During the Ratio Alignment process, the resistors in each of the three 1:10 ratio networks
are reconfigured into serial and parallel combinations. A dynamic internal Wheatstone
bridge configuration is setup using the internal voltage source, resistor ratio network, and
internal null detector to automatically self-align each 1:10 ratio.
