In both of the following configuration sections, INPUT and OUTPUT, conditionals are used. A conditional is an if-then type statement that can be evaluated by the system as either true or false. Conditionals are used to filter the data-flow in the LSO system by turning on and off data-paths. The use of conditionals is explained in greater detail in the INPUT and OUTPUT sections. Conditionals may be constructed using some basic rules.
The first four rules state that a condition may consist of a conditional expression, a Boolean on-off switch, a display, or a string expression. The remaining rules further define what each of these may consist of. An example conditional expression would be:
If this were true then the network tags that were listed below the condition would be transmitted or input depending on which list the condition was in. Note that for a digital table location 1 signifies ON and Ř is used for OFF. The condition:
is true if the status FLG is set to 1. An example Boolean condition would be:
With this condition all the listed network tags will always be active. Another type of basic condition consists of a display number such as:
If this display was active then the tag list would be active. An example string expression might be:
Note that in this case the first item must be a string table location. The operator may only be “=” or “<<>>”. The last item must be a string delimited by quotation marks.