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7.13 RD400 ALARM INPUT MODULE
The RD400 alarm input module is an eight (8) input alarm sensing card developed for
use in the MAXPRO-Net I/O subrack equipment. The RD400 module has its own
microprocessor that is designed to simultaneously monitor all eight input circuits and
report any change of state to the subrack controller microprocessor.
7.13.1
Contact Closure or End-Of-Line Modes
RD400 modules with revision 6 hardware onwards are DIP switch selectable between
open/short circuit sensing, and 10KΩ EOL resistor sensing. Set SW1-1 OFF for contact
closure mode, and ON for 10KΩ end-of-line mode.
CC Mode
When configured in the CC mode the RD400 will detect contact state changes
accordingly to the NO/NC setting as defined in the Alarm Input table in SETMAX.
EOL Mode
In the EOL mode (end-of-line) a setting of NC in SETMAX will cause an alarm to become
active when the alarm loop becomes either open or short circuit (unsealed), conversely
in the NO mode the alarm will become active when the loop is in the "sealed" position.
7.13.2
Sensing
Each input is checked in approximately 2 μsec, so even with all input circuits enabled an
alarm condition can be recognized in less than 16 μsec. There is an alarm de-bounce
period of 20μsec, so an alarm input has to stay unchanged for this period before the
alarm condition is reported.
The LED indicators on the front edge of the alarm input module indicate an ACTIVE
ALARM state, not the actual input logic level. Only enabled alarm inputs will display on
the LED indicators.
Rev. C
WARNING: The following data refers to RD400 modules
of revision-6 hardware and above.
7.13-1
HMXMU001018
10/06
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