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<CT
n
>
Cyclic Data Timeout
Mapped Variables
Description
A mechanism to warn that an input variable has not been updated for (
n
x 10) Seconds
Parameters
n
= 0 to 255
- Multiples of 10 Seconds
Initial Value
0, no timeout active
Modes
All Modes
Notes
If valid data is not regularly sent to each input value then there is a risk that an operator might take
some inappropriate action in response to stale data. A mechanism has been built into the display that
indicates when the data is older than a predetermined timeout value. The data is displayed as
BAD
if
the timeout value has been exceeded, but the “Status” remains unchanged. Sending valid data once
again to the input variable will display the value normally, marked
GOOD
or
BAD
according to the
“Status”.
As the acceptable timeout value is totally dependant on the application and the host capabilities, it is
adjustable from 10 Seconds to 40 Minutes. For simple applications the timeout value can be set to 0
which disables the facility.
The parameter
n
sets a timeout period of
n
x 10 seconds.
n
= 0 deactivates the timeout function.
Uses
The <CT> command allows:
•
Users to be warned that displayed variable may be out of date
Example
<SO3>
Select a four variable screen
The “Wind Speed” reading is shown here as being older than the
timeout value
<SO4>
Change to a single variable plus bargraph
<SV3>
Show the third input (In our case, Wind Speed)
The bargraph, is drawn as a dotted outline showing that it is invalid
Gotchas!
Despite the similarity in the name, the <TO> Timeout command is fundamentally different and are
not usually used in conjunction with each other.
See Also
CD
Cyclic Data
CV
Cyclic Variable
TO
Timeout
