B&K Precision 1796 - Manual - Manual (Page 9)

4.4 If load considerations require that the output power distribution terminals be re-
motely located from the power supply ,then the power supply output terminals should
be connected to the remote distribution terminals via a pair of shielded or twisted
wires and each load should be separately connected to remote distribution terminals.
4.5 Positive or negative voltage can be obtained from this supply by grounding either
one of the output terminals or one end of the load. Always use two leads to connect
load to the supply, regardless of where the setup is grounded. This will eliminate any
possibility of the output current return paths through the power source ground which
would damage the line cord plug. This supply can also be operated upto ±300V DC
above ground, if neither output terminal is grounded.
4.6 REMOTE SENSING :
Warning : Do not Operate the Unit in'REMOTE SENSE' mode without en
suring proper 'REMOTE / 4 TERMINAL' Connections. Serious
Damage to Unit or Equipment under test could result.
Remote sensing is used to maintain good regulation at the load and reduce the
degradation of regulation which could occur due to the voltage drop in the leads
betweeen the power supply and the load. Remote sensing is accomplished by
connnecting the load to remote sense terminals on the front panel. The leads from
the sensing( +S and -S) terminals to the load will carry much less current than the
load leads and it is not required that these leads be as heavy as the load leads.
However, they must be twisted or shielded to minimize noise pickup.
For reasonable lengths of load leads, remote sensing greatly improves the
performance of the supply. However, if the load is located at a considerable distance
from the supply, added precautions must be observed to obtain satisfactory
operation. Notice that the voltage in the load leads subtracts directly from the avail-
able output voltage and also reduces the amplitude of the feedback error signals
that are developed within the unit. Because of these factors, it is recommended that
the drop in each load lead does not exceed 0.5Volts.
NOTE : Due to the voltage drop in load leads, it may be necessary to
readjust the current limit in the remote sensing mode.
Observance of the precautions in para. 4.8 and 4.9 will result in a low dc output
impedance at the load. However, another factor that must be considered is the
inductance of long leads.This causes a high ac impedance and could affect the
stability of the feed back loop seriously enough to cause oscillations. If this is the
case, it is recommended that the following actions be taken :
a)
Adjust R145 to remove oscillations, or to achieve best possible transient
response for given long load lead configuration.
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