csmstr - Omega Engineering

DATA AVAILABILITY
CRIMSON USER MANUAL - MODULAR CONTROLLER
DATA AVAILABILITY
Crimson’s communications infrastructure reads only those data items that are required for the
current page. This means that when a page is first selected, certain data items may not be
available. For a display primitive, this is no problem, as the primitive simply displays an
undefined state (typically a number of dashes) until the data becomes available. For actions,
though, things can get more complex.
For example, suppose a local action increases the speed of a motor by 50 rpm. If the motor
speed is not referenced on the previously displayed page, then, when the page is first
displayed, Crimson will not know the current speed, and will thus be unable to write the new
value. To handle this, if the operator attempts to perform an action for which the required data
is not available, the Master module will display a “NOT READY” message until the key in
question is released. The operator must then wait a short while, and try the operation again. In
practice, communications updates normally take place quickly enough that even the most
nimble-fingered operator will be hard pressed to get the message to appear, but since it may
on occasions be seen, it is worth explaining.
A slightly more complex issue comes about if the action defined by a page’s On Select
property is unable to proceed because it also finds that required data is not available. Here,
Crimson will wait up to thirty seconds for the data to arrive. If it does not, the action will not
be performed, and a “TIMEOUT” message will be displayed for the operator. This timeout
mechanism is required to avoid problems should a communications link become severed.
NOTES FOR EDICT USERS
Users of Red Lion’s Edict-97 software should note…
• Pages no longer have text and graphic layers, as all primitives are graphical in
nature. This means that the concept of a page format is similarly redundant.
• Page categories have been replaced with system primitives. Where Edict would
use an entire page for its alarm viewer, for example, the corresponding system
primitive can be used to allocate as little or as much of the display as is required.
• The actions defined by double-clicking a key replace the global and local event
maps. If your application used more than one row per event, you will most likely
need to use a program to implement the required logic.
• Events such as comms update complete and one-second tick have been removed,
as most of the actions performed by such events can now be handled via other
mechanisms. For example, comms update complete was often used to move data
between devices. This can now be performed using the protocol conversion
functionality of the Communications window. In addition, these events were
often misused and led to the creation of overly complex databases.
• While Edict would typically manage something between two and five display
updates per second, Crimson is designed to redraw the display every 100msec,
thus providing, for example, smoother operator feedback during data entry.
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