Monroe Electronics Electrostatic Fieldmeter - Static Monitor - model 177A - Manual (Page 14)

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As a truly uniform field does not usually occur in most practical measurement situations using the
1036F probes, partly due to the introduction of the grounded probe itself, one must either:
 Improve the geometry by establishing a grounded plane (shroud) through which the fieldmeter
probe can view the field under consideration. Refer to figure 6 on page 9. (see also
Application Note –0003 in Appendix.)
 Establish a correction factor for the data, or
 Accept relative data. In many cases, this is acceptable practice once a fixed geometry is
established and related to the real electric field.
Cables:
Both types of probes are normally equipped with 10-foot-long cables and subminiature D connectors
that mate with Monroe Electronics Model 177A. This is Option 1 of 6 available wiring options – see
Appendix A – Probe Connection Options for details. The first 3 options are for non-hazardous (non-
classified) locations where there are no Intrinsic Safety (IS) considerations. The last 3 options are for
hazardous (classified) locations where IS must be considered as part of the installation and barriers
are in use.
Extension cables are available from Monroe in lengths up to 1000 feet, which is the maximum
permissible length. These extension cables may be ordered in any length (up to 1000 feet) by part
number 1036/12-nnnn, where nnnn is the length in feet.
The cable exit on Model 1036E is supplied through a packing gland which is screwed into a ½"-14
NPT tapped hole in a boss on one end of the housing. Inside the housing, the probe is plugged into
a terminal block to which the cable attaches. Where it is desirable or necessary to connect Model
1036E probes to Model 177 Static Monitors with conduit, the original cable and packing gland can be
removed and the cable replaced by any length (up to 1000 feet) pulled through the conduit with a
connector on only the Model 177 end. Refer to Appendix A – Probe Connection Options, Options 3,
4 or 6 (depending on whether IS must be considered) for details.
Purging:
Any "contamination" present in the probe or near the measurement will have an adverse affect on
performance. When insulative particles or liquid becomes charged and enters the probe or attaches
near the aperture of the probe, it becomes a source of measurement error and drift. Less obvious is
the influence of gaseous atmospheric constituents, including aerosols, which contaminate the probe
by altering the contact potentials between critical surfaces.