Rockwell Automation 1442 Eddy Current Probe System - Manual (Page 51)

Rockwell Automation Publication ICM-UM004C-EN-E - February 2014 51
Appendix
A
Wire the Unit to a Monitor System
The 1442 Series Probe System is designed to satisfy the API-670 standard. Any
monitor designed to connect API-670 probes can be used with these sensors.
Consider the following recommendations when wiring the probe driver to a
monitor:
· Use a good quality instrumentation cable with three-conductor stranded
wire and shield.
– Wire must be rated with a maximum capacitance of 60 pF/ft
(197 pF/m) and inductance of 0.3 μH/ft (1 μH/m).
– Use wire with insulation suitable for the environment and with
adequate tensile strength and flexibility for the application.
– Use wire with a foil shield for use in environments where radio
frequency interference (RFI) may be present. Use a wire with a braid
shield for environments where electromagnetic interference (EMI) may
be present.
– Use 0.75…1.25 mm2 (18…16 AWG) gauge wire.
· Make sure the wire is isolated from power cables and any other wiring that
may be transmitting high-voltage power or control signals.
· Any cable transmitting pulse-type vibration signals such as a phase marker
or speed pulse must be isolated from displacement and vibration signals.
· Run wire within conduit and cable trays and as per any local electrical
codes.
· Do not exceed a wire length of 500 m (546.81 yds). However, limiting the
length to 300 m (328.08 yds) transmits vibration signals in the 0…10 kHz
frequency range with minimal attenuation. When longer lengths are
needed the capacitance of the cable and the desired frequency response of
the system must be considered.
· In most cases, ground the cable shield at only one point, generally at the
monitor.