Section 4: Using the Model 9100: Interconnections 4.2-1
Final Width = 215mm
4.2 Interconnections
4.2.1 Introduction
This sub-section deals with the leads used to connect the 9100 to UUTs, and suggests the
advantages of using the Model 9105 Lead Set for external connections.
4.2.2 External Leads — Specification Degradation
The 9100 Accuracy Specification is delivered at the front panel terminals.
Degradation of the specification at the UUT can occur if care is not taken to select the
correct type, length and terminations for the external leads. This applies particularly to
the outputs of HF AC Voltage at milliamp levels and HF AC Current. In addition, for
accurate thermocouple simulation, extension leads of the correct materials must be used
to avoid spurious junctions, although this also applies with the use of the 9105 leadset.
4.2.3 Model 9105 Lead Set
The design of the Model 9105 optimizes the connections between 9100 and UUT, in order
to deliver the specification for the outputs of all functions at the input terminals of all
UUTs. It also provides a convenient screened work mat which permits easy connection
to the UUT using leads of defined short length, which are also provided.
It is highly recommended that the 9105 Lead Set be used for all hand-held UUTs.
N.B. The 10-turn and 50-turn current coils, which are used to calibrate clamp meters at
high DC and AC current values, should not be placed on the work mat, as this
incorporates a steel core.
E-M Interference:
Noisy or intense electric, magnetic
or electromagnetic fields close to
instruments or connectors can disturb
the measurement circuit.
Some typical sources are:
- Proximity of large electric fields
- Fluorescent lighting
- Inadequate screening, filtering or
grounding of power lines
- Transients from local switching
- Induction and radiation fields of
local E-M transmitters
- Excessive common mode voltages
between source and load
The disturbances may be magnified
by the user’s hand capacitance.
Electrical interference has greatest
effect in high impedance circuits.
Separation of leads and creation of
loops in the circuit can intensify the
disturbances.
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