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Wilcoxon Sensing Technologies
20511 Seneca Meadows Parkway, Germantown MD 20876, USA
Amphenol (Maryland), Inc d/b/a Wilcoxon Sensing Technologies
Tel: +1 (301) 330-8811
Tel: +1 800 WILCOXON
Fax: +1 (301) 330-8873
www.wilcoxon.com
78001 Rev B 09/17
PC420 series installation guide
4-20mA series transducers
Loop Powered Sensors (LPS®)
Caution: This guide should be read carefully before installation
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78001 Rev B Page 2 of 8
Safety section
PC420-series vibration transducers can be safely installed when the instructions in this manual are
carefully followed. This section summarizes the safety considerations. Reminders in the form
described below, will appear in the detailed instructions to assure operator awareness of these safety
considerations. Qualified personnel should install the PC420-series vibration transducers only after
becoming thoroughly familiar with this manual.
WARNING: This symbol is used in the instruction manual where the safety of the operator
must be considered. The instruction manual should be consulted and read carefully.
CAUTION: This symbol is used when caution is needed to prevent damage to equipment. It is used
where careful attention to certain procedures described in the instruction manual is needed. This
symbol is also used to emphasize procedures other than normal operating procedures.
Safety summary
1. The PC420-series vibration transducers covered by this installation guide do not require any
special precautions, protective devices or equipment.
2. Because the PC420-series vibration transducers are designed to be mounted on rotating
industrial equipment, personnel involved with the installation of PC420-series vibration
transducers should be familiar with all plant safety requirements before beginning installation.
3. The PC420-series vibration transducers are hermetically sealed.
4. There are no user serviceable parts within the PC420-series vibration transducers.
5. Use common sense and avoid haste during the installation of the PC420-series vibration
transducers!
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78001 Rev B Page 3 of 8
Contents
1.0 Introduction………………………………………………………… 4
2.0 Applicable models………………………………………………… 4
3.0 Mounting……………………………………………………………. 5
3.1 Threaded stud…………………………………………………… 5
3.2 Cementing pad.......................................................................... 5
4.0 Cabling……………………………………………………………… 6
5.0 Technical assistance…………………………………………...... 8
5.1 Technical assistance…………………………………………… 8
5.2 Customer service……………………………………………….. 8
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78001 Rev B Page 4 of 8
1.0 Introduction
This guide is designed to assist the user in the physical installation and wiring of the Wilcoxon
Sensing Technologies PC420 series of vibration transducers. It is presumed that the user has already
selected the mounting location and model of PC420-series transducer to be used. Assistance for the
selection, location, and use of these transducers is contained in the “Application Guide for PC420-
series LPS® Transducers” available from Wilcoxon Sensing Technologies.
2.0 Applicable models
This installation guide is intended for use with the PC420-series units with either velocity output
(PC420Vx-yy) or acceleration output (PC420Ax-yy) as well as those with dynamic output (PC420xxyy-DA or PC420xx-yy-DV).
PC420Vx-yy and PC420Ax-yy
The velocity or acceleration units are two-wire devices. The model number designations have a root,
PC420V or PC420A, designating the basic 4-20mA output as either velocity or acceleration. The
PC420V-series are velocity 4-20mA output. The PC420A-series are acceleration 4-20mA output. The
x-yy portion of the model number designates the type of signal processing and the full-scale range.
The signal types are VR or AR for “root-mean square (rms)” signal output and VP or AP for “peak”
signal output. The table below summarizes the models and full-scale ranges available.
Table 1 – PC420 model numbers for 2 wire output
PC420VR-yy
4-20mA velocity, rms
PC420VP-yy
4-20mA velocity, peak
PC420AR-yy
4-20mA acceleration, rms
PC420AP-yy
4-20mA acceleration, peak
PC420Vx-yy-Dz and PC420Ax-yy-Dz
The dual output units are available with both the acceleration and velocity 4-20mA signal outputs as
listed above and a dynamic signal output. The dynamic signal can be either velocity or acceleration,
-DV or-DA. This allows the user to select both the type of 4-20mA loop output signal and the type of
dynamic signal desired. The acceleration dynamic output (100 mV/g) and the velocity dynamic signal
is 100 mV/ips.
Table 2 – PC420 model numbers for dynamic signal output
PC420xx-yy-DA
Dynamic acceleration output, 100 mV/g
PC420xx-yy-DV
Dynamic velocity output, 100 mV/ips
-yy full scale
Velocity
Acceleration
-05
0.5 ips
5 g
-10
1.0 ips
10 g
-20
2.0 ips
20 g
-30
3.0 ips
N/A
-50
5.0 ips
N/A
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78001 Rev B Page 5 of 8
3.0 Mounting
When using vibration transducers to measure vibration, the transducer must have direct contact
with the machine surface. The transducer should be mounted in a location that minimizes the
vibration transmission route through the machine. Avoid mounting the transducer on thin sections
or vibration free areas (antinodes).
Direct stud mounting, epoxy and cementing pads are used for permanent installations. The
transducer can be directly mounted by tapping a hole into the structure and attaching the transducer
with a threaded stud. Cementing pads can be epoxied in place of the tapped hole; the transducer is
then mounted to the pad. In some cases, the transducer can be mounted directly to the machine
using epoxy.
Cementing pads approach the capabilities of stud mounts when used properly. The following
are recommended permanent mounting procedures. Alternative procedures should be
evaluated with respect to frequency response, grounding, and installation requirements.
Adhesive selection is critical for long-term reliability; please consult Wilcoxon Sensing
Technologies before other procedures and materials are used.
3.1 Threaded Stud
Stud mounting requires a tapped hole drilled directly into the structure. A
threaded stud provides electrical and mechanical connection between the
transducer and machine. The transducer requires a flat spot-faced surface
with a perpendicular tapped hole. The spot face must be 1.1 times larger
than the diameter of the transducer housing to ensure flush mounting. Burrs
between the transducer and the machine must be eliminated. The centerline of
the tapped hole should be perpendicular within 1° of the mounting surface to
ensure no gaps are present between the base of the transducer and the
structure. The tap drill and spot face can be machined in one step using the
Wilcoxon ST101 Spot-Face tool. The ST101 will face the surface and drill the tap
hole perpendicular to the face in one operation. The drill supplied with the ST101
is sized for a 1/4-28 tap. Additional guidance on mounting procedures and techniques can be
obtained from Wilcoxon Sensing Technologies Technical note 21, Mounting considerations. It is
available for download from the Wilcoxon web site at www.wilcoxon.com.
The PC420-series transducers should be torqued to a value between 26 - 30 inch-pounds.
3.2 Cementing pad
Cementing pads eliminate tapping into the structure, but provide high frequency
capability approaching stud mounts. The PC420-series transducers should be
mounted using a Wilcoxon SF8 cementing pad. The flat side is bonded to the
machine with an appropriate adhesive. The opposite side contains a 1/4-28 stud for mounting the
transmitter. Additional guidance on cementing pad mounting procedures can be obtained from
Wilcoxon’s Technical note 21, Mounting Considerations. It is available for download from the
Wilcoxon Sensing Technologies web site at www.wilcoxon.com.
The PC420-series transducers should be torqued to 26 - 30 inch-pounds.
SF6 stud
SF8 cementing pad
ST 101
Surface preparation
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78001 Rev B Page 6 of 8
J9F cable
R6Q connector
4.0 Cabling
Wilcoxon Sensing Technologies has cabling available with connectors already installed for use
with the PC420-series vibration transducers. These cables are two-conductor, shielded, twisted
pair wire for the 4-20 mA loop output and three-conductor, shielded, twisted wire for the dual
output transducers. Isolated connectors are recommended for use with PC420-series
transducers to eliminate the possibility of ground loops when wiring to 4-20 mA loop inputs. The
cables listed below all use isolated connections for the shield at the transducer end of the cable
so that the shield will not be grounded at the transducer.
Stock cable model numbers for use with the PC420-series transducers are:
Table 3: Standard cable lengths for stock cables
Length
Cable
Use with
Feature
5 m / 16 ft
R6W-0-J9T2A-16
2-wire PC420
IP67 connector, Teflon, braided shield
R6W-0-J9T2A-16
2-wire PC420
IP67 connector, Teflon, braided shield
R6W-0-J9F-16
2-wire PC420
IP67 connector, Teflon, braided shield
R6W-0-J9F-16
2-wire PC420
IP67 connector, Teflon, braided shield
R6GQI-0-J9T3A-16
Dual output PC420
IP68 connector, Teflon, braided shield
Length
Cable
Use with
Feature
10 m / 32 ft
R6QI-0-J9T2A-32
2-wire PC420
IP68 connector, Teflon, braided shield
R6W-0-J9F-32
2-wire PC420
IP67 connector, Teflon, foil shield
R6QI-0-J9F-32
2-wire PC420
IP68 connector, Teflon, foil shield
R6GQI-0-J9T3A-32
Dual output PC420
IP68 connector, Teflon, foil shield
Cables can be manufactured in other lengths for an additional charge.
Connection
The PC420 Series Transducers are loop powered devices. There is no additional
signal conditioning equipment required for the transducers to function. The tables
below show the cable conductor wire colors for the J9T2A, J9T3A and J9F cable
assemblies listed in the previous section. The shield of the cable does not make electrical
contact with the case of the PC420 series transducer. For other cable configurations,
contact your Customer sales representative at 1800WILCOXON.
Table 4: Output pin and cable conductor color designations for two wire PC420 series transducers
PC420xx-yy pin
Function
J9T2A
J9F
A
Loop power +
White
Red
B
Loop return -
Black
Black
Table 5: Output pin and cable conductor color designations for dual output PC420 series transducers
PC420xx-yy-Dz pin
Function
J9T3A
A
Loop power +
Red
B
Loop return/dynamic common -
Black
C
Dynamic signal output
White
J9T2A cable
R6W connector
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78001 Rev B Page 7 of 8
Figure 1: Typical two wire installation wiring
CAUTION: The common for the dynamic output is also the return signal for the 4-20mA loop wiring.
Connecting this pin to ‘ground’ will usually short out the 4-20mA loop return resulting in a loss of the
4-20mA signal. The dynamic output is designed to be used by portable data collectors where no
direct connection to ground exists. It can also be used by on-line systems when their signal input is
galvanically isolated from ground.
Figure 1: Typical dual output installation wiring
CAUTION: The common for the dynamic output is also the return signal for the 4-20mA loop wiring.
Connecting this pin to ‘ground’ will usually short out the 4-20mA loop return resulting in a loss of the
4-20mA signal. The dynamic output is designed to be used by portable data collectors where no
direct connection to ground exists. It can also be used by on-line systems when their signal input is
galvanically isolated from ground.
No
connection
at sensor
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78001 Rev B Page 8 of 8
5.0 Technical assistance
5.1 Technical assistance
For technical assistance, please contact Wilcoxon Sensing Technologies at 301-330-8811 or
email info@wilcoxon.com.
5.2 Customer service
For all customer service inquiries, please call 301-330-8811 or email info@wilcoxon.com.
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