CAAPE User's Manual - ALSTOM Signaling Inc.

Simulator Reference12.6.7. Special Hardware Input / Input Message Variable ConsiderationsIn some cases, it is necessary to set the state of a hardware input or the value of aninput message bit rather than setting the state of its associated variable. For example, ifa variable is a bit in an unlatched serial control, its value is automatically set False at thebeginning of a cycle unless a new message is received. Setting the variable True with aTRUE command may not be reliable; the automatic message clearing process mayclear the variable before the application logic has a chance to use it.To set control message bits or hardware input states directly, use these commands(described below):• MSGINF, MSGINT - set input message bit False or True and set message flag toindicate new data available. The value is input as new message data at thebeginning of the next cycle and is held for at least one cycle depending on whetherthe message is unlatched or latched.• HWINFLASH, HWINOFF, HWINON - set hardware input flashing, off or on. Sets thehardware input state, which updates the associated variable at beginning of the nextcycle.For latched control messages, associated variables are not automatically cleared eachcycle. Using TRUE or NTRUE on latched control bit variables is safe because thesimulator does not automatically clear them unless a new message is received.P2512A, Rev. Oct/09 12–62 Alstom Signaling Inc.