The click plc has a real-time clock that will allow us to control outputs based on a date or time of day. This real-time clock (RTC) can be set from the click programming software or through the program of the controller. Our programs in the click can use the following calendar and clock values:
SD19 – RTC Year – 4 digits (2021)
SD20 – RTC Year – 2 digits (21)
SD21 – RTC Month – (00 to 12)
SD22 – RTC Day – (00 to 31)
SD23 – RTC Day of the Week – 1 Sunday to 7 Saturday
SD24 – RTC Hour – (00 to 23)
SD25 – RTC Minute – (00 to 59)
SD26 – RTC Second – (00 to 59)
We will be using the RTC – Real Time Clock in a sample program. This program will turn on an output Monday to Friday from noon until 1 pm. It will also adjust for daylight savings time. Let’s get started. Keep on Reading!
A watchdog is a piece of code that will timeout when an error occurs in our program. It will usually cause the CPU (program/sketch) to stop or reset.
We will now look at the instructions for the watchdog timer in productivity blocks. This includes the Configure Watchdog, Start Watchdog, Stop Watchdog, and Pet Watchdog.
Our sample sketch will modify the P1000 Expansion Digital Inputs and Outputs Part 2 program by adding a watchdog timer.
Let’s get started. Continue Reading!
Time instructions in our productivity blocks programming (Arduino sketches) consist of runtime (ms), runtime (us), delay ms, and delay microseconds us.
We will be looking at each of these instructions that are available for our program using productivity blocks. Delay instructions in our sketches should be used with caution. They will pause our program for the delayed time, not allowing other parts of the program to function. We will be looking at this and the method to do the exact same delay functions without pausing your program.
A sample program will be discussed to demonstrate the time functions in our program. Let’s get started. Continue Reading!
Timers are present in just about every PLC program that I have seen. A timing chart is a secret behind understanding the timer that you need in your application. Making a timing chart before writing the program will ensure that all of the information will be accounted for. The secret to using timers is a good review of using these timing charts.
PLC Fiddle has three different timing instructions for us to use in our programs. On-Delay, Off-Delay, and Retentive Timers. We will discuss the timer parameters and the three different instructions. Our timer challenges will help you gain a good understanding of how timers work in the PLC. Let’s get started. Continue Reading!
Just about every programmable logic controller (PLC) program will include a timer instruction. The Productivity 1000 Series PLC has several different timer instructions for your program. We discussed the timed coil (TMC) and flasher coil (FLS) last time as part of the contacts and coil discussion. (Contact and Coil Instructions – Video)
We will now look at using the Simple Timer (STMR) and the Timer (TMR) instructions in the productivity suite software. Let’s get started. Continue Reading!