Specifications

Table Of Contents
APPENDIX C: EVENT PROGRAMMING
Page 185 MRC-565 Packet Data Radio Operations & Maintenance
Example 1: A Scanned Event - Vehicle Tip-Over Detection
Suppose the MRC-565 is wired to detect a vehicle tip-over using the CTS and DTR signals and a
gravity switch that closes if it does not remain mostly upright. The CTS output is used to enable
tip-over detection. The DTR input is the signal on which tip-over event is detected. Normally
open, the switch prevents DTR from receiving the CTS signal. If CTS is enabled and the vehicle
tips over such that the switch closes, the CTS signal is presented to DTR.
To make the tip-over detection mechanism function, the CTS signal must be enabled so that it
can be detected at DTR should the switch close. A good time to enable CTS – set CTS to high –
may be when the MRC-565 is powered up. The command EVENT,RESET,SET,CTS will do
this. The event is RESET. The action is SET,CTS. The "ignition" bit should also be set in the
status word. The bits of the status register are numbered from low order to high order, BIT0
through BIT15. The COLLISION bit is the same as BIT0, and the action "COLLISION" is used
instead of "SET,BIT0" for clarity.
The command EVENT,DIOHI,DTR,16,160,COLLISION defines an event that creates a
vehicle collision report if the DTR signal is high for 1 second (16 sixteenths of a second).
Collision is defined as the vehicle being tipped over. The event will clear and be ready for
another event if the signal is low for 10 seconds (160 sixteenths of a second). "DIOHI" means
"discrete I/O high" and "DTR" specifies the DTR discrete input. The parameters
"DIOHI,DTR,16,160" define the event. The parameter "COLLISION" defines the action.
The User will create the event table with the following commands:
MCC-545 RF Modem
CTS
DTR
Gravity
Switch
CTS is set to 5V on power-up, DTR is low if switch is open
DTR will go high when the switch is closed
EVENT,STOP
EVENT,DEL,ALL
EVENT,RESET,SET,CTS
EVENT,RESET,SET,BIT2
EVENT,DIOHI,DTR,16,160,COLLISION
EVENT,START
SAVE