In several previous lessons we have been discussing modifying the values of various datatypes in a watch table. In this lesson we will introduce you to forcing. Forcing is similar to modifying with some subtle differences. One of those differences is when input or output addresses are forced, the logic solve has absolutely no bearing on the result of a forced address. We’ll talk about the ins and outs of forcing and some safeguards that you need to keep in mind while using this function. Forcing is sometimes a necessary option so let’s open up this lesson and see how to best deploy it.
In this lesson we will describe the difference between modifying addresses and forcing them. This lesson discusses what happens with either of these functions when the PLC power is turned off or when you are connected with your computer and you disconnect. The force function has an external indic...
In previous lessons we have discussed the Process Image Input or PII and its purpose. In this lesson we discuss the size of the PII and what will be required of you to know, as the programmer, when it comes to being able to access your I/O when the boundary of the PII is exceeded. Each PLC has a ...
In the previous lesson we discussed the Process Image Input or PII and its size. We wrote a simple move instruction to access an analog input only to find that just as soon as we downloaded it to the PLC, the PLC faulted and went into stop mode. In this lesson we will discuss the PII further and ...
7 Comments