Rockwell Automation 1440-VLF02-01RA XM-121 Absolute Shaft Module - Manual (Page 9)

1 Publication GMSI10-UM014D-EN-P - May 2010
Chapter
1
Introduction
This chapter provides an overview of the XM-121 Absolute Shaft module. It
also discusses the components of the module.
Introducing the Absolute
Shaft Module The XM-121 Absolute Shaft module is an XM-121 Low Frequency Dynamic
module with alternative, XM-121A, firmware loaded onto it. The XM-121 is
part of the Allen-Bradley™ XM
®
Series, a family of DIN rail mounted
condition monitoring and protection modules that operate both in stand-alone
applications or integrate with Programmable Logic Controllers (PLCs) and
control system networks.
Shaft Absolute is the measure of the shaft’s motion relative to free space – its
absolute motion. In the Absolute Shaft module, the Shaft Absolute
measurement is calculated by summing signals of both an eddy current probe,
measuring the motion of the shaft relative to the case, and an Allen-Bradley
9000 series sensor (accelerometer or velocity) measuring the absolute motion
of the case.
In addition to vibration inputs, the Absolute Shaft module accepts one
tachometer input to provide speed measurement and order analysis functions.
It also includes a single on-board relay (expandable to five with an XM-441
module), two 4-20 mA outputs, and a buffered output for each input. The
module can collect data under steady-state and startup/coast-down conditions,
and monitor up to nine alarms making it a complete monitoring system.
For information about See page
Introducing the Absolute Shaft Module 1
Absolute Shaft Module Components 2
Using this Manual 3
IMPORTANT
This manual only describes how to install and use the
XM-121 Absolute Shaft module. For information about the
low frequency dynamic measurement module, refer to the
XM-120/121 Dynamic Measurement Module User Guide.