Rockwell Automation 1440-VLF02-01RA XM-121 Absolute Shaft Module - Manual (Page 147)

139 Publication GMSI10-UM014D-EN-P - May 2010
Glossary
alarm
An alarm alerts you to a change in a measurement. For example, an alarm can
notify you when the measured vibration level for a machine exceeds a
pre-defined value.
Automatic Device Replacement (ADR)
A means for replacing a malfunctioning device with a new unit, and having the
device configuration data set automatically. The ADR scanner uploads and
stores a device’s configuration. Upon replacing a malfunctioning device with a
new unit (MAC ID 63), the ADR scanner automatically downloads the
configuration data and sets the MAC ID (node address).
band
A frequency range, such as the frequency range between 1,800 and 3,200 Hz.
baud rate
The baud rate is the speed at which data is transferred on the DeviceNet
network. The available data rates depend on the type of cable and total cable
length used on the network:
The XM measurement modules’ baud rate is automatically set by the bus
master. You must set the XM-440 Master Relay module’s baud rate. You set the
XM-440 to 125 kb, 250 kb, 500 kb, or Autobaud if another device on the
network has set the baud rate.
Bit-Strobe
A multicast transfer of data sent by a master device to all the XM slaves on the
network. The bit-strobe command message contains a bit string of 64 bits (8
bytes) of output data, one output bit per node address on the network.
bus off
A bus off condition occurs when an abnormal rate of errors is detected on the
Control Area Network (CAN) bus in a device. The bus-off device cannot
receive or transmit messages on the network. This condition is often caused by
corruption of the network data signals due to noise or baud rate mismatch.
Maximum Cable Length
Cable 125 K 250 K 500 K
Thick Trunk Line 500 m (1,640 ft.) 250 m (820 ft.) 100 m (328 ft.)
Thin Trunk Line 100 m (328 ft.) 100 m (328 ft.) 100 m (328 ft.)
Maximum Drop Length 6 m (20 ft.) 6 m (20 ft.) 6 m (20 ft.)
Cumulative Drop Length 156 m (512 ft.) 78 m (256 ft.) 39 m (128 ft.)