Metrix ST5484E - Specifications and Ordering

Doc# M9162• REV AB (April 2019) Page 7 of 12
5. CONNECTION TO PLC OR OTHER INDICATING INSTRUMENT
The rst step in conguring the PLC, DCS, or other recording instrument is to determine the source
of power. The ST5484E requires loop power. Some analog input channels on a PLC or DCS, for
example, provide this power from within. If they do not provide power, an external power supply
must be provided. Connect the transmier eld wiring using standard instrumentaon pracces.
Scaling of the display is on the basis of the range of the transmier. The measurement parameter
name is “vibraon” and the units are “in/s” (inches per second) or “mm/s” (millimeters per sec-
ond). The example below is based on a standard 1.0 in/s transmier.
6. TYPICAL TRANSMITTER PLACEMENT
The ST5484E measures seismic vibraon (i.e., vibraon velocity) at the aachment point on the
machine, using engineering units of in/s (inches per second) or mm/s (millimeters per second)
depending on the selected ordering opon. The transmier’s sensive direcon is through the long
axis of its cylindrical body. It will not measure side-to-side moon.
Typical transmier mounng for casing vibraon measure-
ments is in the horizontal direcon at the bearing housings
as depicted in Figure 2. The horizontal direcon usually
incurs more vibraon because most machines’ foundaon
constrains vercal vibraon more than horizontal vibraon.
A horizontal mounng arrangement is also depicted in Figure
3, but with addional detail showing typical accessories.
When ying leads are ordered, a 24- or 72-inch length may
be specied using ordering opon D on the Metrix product
datasheet 1004457. These leads may be cut to length and
then spliced to eld wiring as shown in Figure 3.
Figure 2
Typical transmier
mounng
When vibraon level
at transmier is…
Transmier output
will be…
PLC (or other) should read…
0.0 in/s (i.e. no vibraon) 4.0 mA (± 0.1 mA) 0.00 in/sec
1.0 in/s (i.e. full scale vibraon) 20.0 mA (± 0.5 mA) 1.00 in/sec
Momentary “jolts” that can occur at start-up, or during some operang condion changes, do not
reect a machine’s steady-state operang condion. To prevent such occurrences from generang
nuisance alarms, program a me delay into the alarm such that the indicated vibraon level must
persist above the alarm setpoint for a preset period of me before an alarm is generated. The
indicated vibraon level must cross the threshold level and stay above it for a preset me before
any alarm acon is taken. A 2- to 3-second delay is normally applied to most machinery. Consult
Metrix if you have a queson about your machine’s operang characteriscs.
Some rough starng machinery may also need a start-up me lockout for alarms. A start-up
lockout is dierent than a me delay. A start-up lockout funcons the same as a me delay, but is
usually set to a much longer me. Both may be needed.