Rockwell Automation T80015 Application Note Trusted SC300E Migration Process - Manual (Page 9)

Trusted TM
AN-T80015
Issue 01 Apr 08 AN-T80015 Page 9 of 16
Alarm and Normal, and these state names will also appear in the log. The point can now
transfer events from the application to the SOE log, which can be collected either by an OPC
client through the Trusted
TM OPC server, or using the Trusted TM SOE collector program
running on a PC.
There is no need to clear the logs. The processor event log contains 200 events and is
cyclically overwritten. The SOE log contains 4000 events and is also cyclically overwritten,
although care should be taken not to create more events than a collector can extract or
events will be lost. The processor event log is stored on power loss in a backup log.
2.4.5. Firmware calls
The SC300E application has calls to the system firmware such as USR3, USR4, FALT etc.
These are user configured and may have bespoke code designed to execute away from the
application ladder. This means that if some of the functions in SC300E systems may need
redesigning and they cannot be translated easily into ladder, structured text etc. Some calls
usually involve system diagnostic functions, and can be replaced by application logic
diagnostic
Some sections of the example system logic have therefore been ignored in the transfer until
their purpose became clear through online testing. This highlights the need for a system test
to unearth all missing functionality, much of which will not be evident until real world
interactions are possible.
2.4.6. Timers
Trusted TM has three timer function blocks TON, TOF and TP. The usual timer is TON which
raises its output true after the input has been true for a preset time.
SC300E has a timer function with two discrete inputs (time and clear) and two discrete
outputs (GE and LT). GE and LT are always the inverse of each other.
Time accumulates when both inputs are on, during which LT is true. If both inputs stay true
until the timeout, GE goes true. If clear goes false, the time is reset to zero and LT goes true.
If time goes false, the time is held.
If both inputs to the timer function are wired to the same source, the timer acts like TON. If
the inputs are separated, then the logic must be examined for the implications of separately
holding or resetting the timer. TON cannot be held, and applications requiring this need a
special function block.