Allen-Bradley 1440-SDM02-01RA, User Manual, Page: 88 / 168

88 Rockwell Automation Publication 1440-UM001D-EN-P - September 2016
Chapter 2 Configure the XM-124 Standard Dynamic Measurement Module
Relay Installed Indicates whether the relay is a physical relay on a module or a virtual
relay. If the relay is a physical relay, then you can set the Failsafe
parameter.
If the relay is a virtual relay, the Failsafe parameter is not used or it is
disabled.
Determines whether the relay is failsafe or non-failsafe.
Failsafe operation means that when in alarm, the relay contacts are in
their ‘normal’, de-energized, or ‘shelf-state’ positions. In other words,
normally closed relays are closed in alarm, and normally open relays are
open in alarm. With failsafe operation, a power failure equals an alarm.
• In failsafe operation:
– The relay is energized when power is applied to the module.
– The relay in a nonalarmed condition has power applied to the
coil.
– In alarm condition, power is removed from the relay coil, causing
the relay to change state.
• For non-failsafe operation:
– Under nonalarm conditions, the relay closes the circuit between
the common and the N.C. (normally closed) terminals.
– Under alarm conditions, the relay changes state to close the
circuit between the common and the N.O. (normally open)
terminals.
• For failsafe operation:
– Under nonalarm (with power applied to the unit) conditions, the
relay closes the circuit between the common and the N.O.
terminals.
– Under alarm or loss-of-power conditions, the relay changes state
to close the circuit between the common and the N.C. terminals.
Table 16 - Relay Parameters (Continued)
Parameter Name Description Options/Comments
XM Configuration
Utility EDS File
Check = Physical Relay Installed = Physical
Relay
Clear = Virtual Relay Not Installed =
Virtual Relay
XM Configuration
Utility EDS File
Failsafe Relay Failsafe Option
XM Configuration
Utility EDS File
Check means failsafe Failsafe
Clear means non-failsafe Nonfailsafe