Specifications

Modifying Running Algorithm Variables
Updating the
Algorithm Variables
and Coefficients
The values sent with the ALG:SCALAR command are kept in the Update Queue
until an ALGorithm:UPDate command is received.
ALG:UPD cause changes to take place
Updates are performed during phase 2 of the algorithm execution cycle (see
Figure 3-8 on page 80). The UPDate:WINDow <num_updates> command can be
used to specify how many updates must be performed during phase 2 (UPDATE
phase) and assigns a constant window of time to accomplish all of the updates that
will be made. The default value for <num_updates> is 20. Fewer updates (shorter
window) means slightly faster loop execution times. Each update takes
approximately 1.4 µs.
To set the Update Window to allow ten updates in phase 2:
ALG:UPD:WIND 10 allows slightly faster execution
than default of twenty updates
A way to synchronize variable updates with an external event is to send the
ALGorithm:UPDate:CHANnel ‘<dig_chan/bit>’ command.
·
The <dig_chan/bit> parameter specifies the digital channel/bit that controls
execution of the update operation.
When the ALG:UPD:CHAN command is received, the module checks the current
state of the digital bit. When the bit next changes state, pending updates are made in
the next UPDATE Phase.
ALG:UPD:CHAN ‘I133.B0’ perform updates when bit zero of
VT1533A at channel 133 changes
state
Enabling and
Disabling
Algorithms
An algorithm is enabled by default when it is defined. However, the ALG:STATe
<alg_name>, ON | OFF command is provided to allow for enabling or disabling
algorithms. When an individual algorithm is enabled, it will execute when the
module is triggered. When disabled, the algorithm will not execute.
NOTE The command ALG:STATE <alg_name>, ON | OFF does not take effect until an
ALG:UPDATE command is received. This allows multiple ALG:STATE
commands to be sent with a synchronized effect.
Programming the VT1419A Multifunction
Plus
Modifying Running Algorithm Variables
Chapter 3 85
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