In the previous lesson, we had a program that contained a comparator instruction and it properly executed our jump instruction. We then changed that instruction to a field input. When we forced that input to true in the simulator, we managed to put our program in an infinite loop, causing a Stop mode in the PLC. In this lesson, we will be working in the simulator again and viewing the diagnostics buffer. We will again make the program enter an infinite loop and while do so, we will check the diagnostics to see what is happening and what message we get with this error.
In some cases you may need to flash a bit in your PLC program. Let’s say that you have an HMI that is not capable of flashing an alarm notification. In that case, you may use the PLC program and one of a number of ways to flash a bit. You can then use that bit on the HMI to indicate a flashing al...
In the previous lesson we talked about the different ways to generate timing pulses or flashing bits within your PLC program. Also, in other lessons, some time ago, we discussed how to generate pulses using timers. In this lesson, we are going to recap how to create these pulses and work with the...
In this lesson, we are going to discuss how to handle alarming. Visual alarm indicators may be lights on the plant floor or alarm symbols on an HMI screen and as common industry standard, an indicator should flash when an alarm occurs but only until acknowledged. After acknowledgement, the indica...
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