3500 Galvanic Isolator Interface Manual
2
2. General
Information
This section describes the Bently Nevada 3500 Galvanic Isolator Interface
system and lists the Bently Nevada 3500 Monitors and transducer systems with
which it is designed to be used.
A Vibration Transducer Interface works in an intrinsically safe system as a
galvanic isolator. This isolator acts as an interface between a transducer
installed in a hazardous environment and a 3500 monitoring system installed in a
safe environment.
Although a galvanic isolator and a zener barrier are both intrinsically safe
interfaces that provide the same level of protection, they work differently. A
zener barrier works by shunting excess current and voltage to ground. A
galvanic isolator provides intrinsic safety by isolating power, ground, and signal
in the hazardous area from the safe area. This isolation removes the need to
provide an earth ground in the hazardous environment. With the exception of the
Aeroderivative Interface Module, all transducers can "float" in the hazardous
environment.
A drawback to using galvanic isolation instead of zener barriers is that galvanic
isolation introduces a small amount of noise and signal inaccuracy to the
transducer output as listed in the data sheet at the end of this manual. This error
can cause some concern in certain applications as described in the section
Checking the Accuracy of the Output Signal, page 5.
The Bently Nevada 3500 Galvanic Isolator Interface can receive inputs from the
following approved Bently Nevada transducers:
•
3300 XL Proximitor
Transducer
•
3300 5 mm/8 mm Proximitor
Transducer
•
7200 5 mm/8 mm Proximitor
Transducer
•
Accelerometer Interface Module (part number 23733-03)
•
Aeroderivative Interface Module (part number 86517) (Velocity Only)
•
3300
REBAM
MicroPROX
Transducer
•
7200
REBAM
MicroPROX
Transducer
The 3500 Galvanic Isolator Interface system can be used in thrust, DC,
Keyphasor and vibration systems. The following 3500 monitors have been
tested with the 3500 Galvanic Isolator Interface system:
•
3500/25
Keyphasor
Monitor
•
3500/40
Proximitor
Monitor
•
3500/42
Proximitor
/Seismic Monitor
•
3500/44 Aeroderivative Monitor
•
3500/50
Tachometer
Monitor
Note: The I/O modules of the above 3500 monitors must be External
Terminations.
