User`s guide

3 - Installation

Figure 3-2. Remote Sense Connections

Remote Sense Leads

Testing has verified stable performance with the sense leads connected up to 20 inches from the phone.

However, for optimum performance, connect the sense leads as close as possible to the phone under test.

To minimize inductance, connect the sense leads as a separate twisted pair.

The sense leads are part of the dc source's feedback path and must be kept at a low resistance (less than

several ohms) to maintain optimal performance. Connect the sense leads carefully so that they do not

become open-circuited. If the sense leads are left unconnected or become open during operation, the dc

source will not regulate the output voltage. See "Open Sense Lead Protection".

Connect the remote sense leads only to the remote sense connections at the output connector and at the

location on the test fixture where you want to sense the output voltage. There must be not be any

continuity from the sense leads to earth ground or from the sense leads to the output leads other than at

the test fixture. The open sense detect circuit will check for continuity in the sense leads when the output

is turned.

Figure 3-3 shows how to connect remote sense leads and load leads when external disconnect relays are

included in the load path.

NOTE: In this arrangement, the output of the unit should be programmed OFF before the relays

are switched. This is because if the load leads are opened before the sense leads, the

overvoltage protection circuit will trip if it is enabled.

Local

Remote

SENSE

LOAD

TWIST PAIR

SENSE

SWITCH OUT

HP 66311A OUTPUT

CONNECTOR

-S - + +S

WIRE RESISTANCE

TWIST LEADS