Metrix ST5484E - Page 10

Doc# M9162• REV AB (April 2019) Page 10 of 12
same frequency band as used for the 4-20mA velocity measurement (refer to opons E and
F on the Metrix Datasheet 1004457).
Observe the following when using this output:
• Only an electrically-isolated or baery-
powered portable vibraon analyzer
should be used when connecng to this
output. Since this is a loop-powered
device, an external ground will aect the
loop output and could cause a false alarm.
• When using a portable vibraon analyzer
or data collector, be sure to turn the
instrument sensor power o.
• Most portable vibraon analyzers have a
low input impedance and they will load
this signal, resulng in aenuaon of as
much as 20% to 30%. Refer to Table 1
which shows the nominal aenuaon
expected for a given input impedance.
• In all cases for all locaons, the use
of this signal is for temporary connec-
on only. Permanent connecon could
violate hazardous locaon installaon
requirements.
• Avoid impacng the transmier or
introducing other mechanical vibraons
when connecng to this output. Such
vibraon could result in spurious alarms
or machinery trips.
• When output is not in use, be sure leads
cannot touch conduit or each other
as this will aect the 4-20 mA current
output.
• Avoid introducing electrical noise when using
this output. Do not use this output with leads
longer than 5m (16 feet). Use of longer leads can
introduce electrical noise and aenuate high-
frequency signal content that may be present in
the raw acceleraon signal.
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6
Table 1
Input Impedance
of Analyzer
dB
Aenuaon
10 MEG 0.01
5 MEG 0.02
2 MEG 0.04
1 MEG 0.09
500 K 0.18
200 K 0.43
100 K 0.84
50 K 1.61
20 K 3.57
10 K 6.10