ACC Automation: PLC & Industrial Control Learning
Practical Tips and Techniques
We will now look at the Game of Simon for our part 5 in this series of building a PLC program. Learning all about bit manipulation and sequencers Simon is a memory game introduced in 1978. It has four colored buttons, each producing a particular tone when it is pressed or activated by the device. … Read more
We are using Modbus TCP protocol, reading ten registers in the PLC, and displaying a bar graph in Excel. e will use Visual Basic for Applications (VBA) to communicate with a PLC. Previously we have used VB6 to communicate Modbus TCP. Sequence for Modbus TCP on Excel using VBA The following steps will be done: … Read more
Utilizing the CX Server DDE Manager will allow us to provide a link to the information in the Omron PLC. This link can be placed on an Excel spreadsheet. Charts, graphs, etc., can be made from the data. We will create links on an excel spreadsheet from a CQM1H and a CP1L PLC. The information … Read more
Sending email messages from the PLC sounds like an easy task. However, very few applications do this on the production floor. This is probably due to the networks involved, and authentication can be complicated. In our example, we will use a restricted Gmail SMTP server so that no authentication will be required. We will walk … Read more
We will apply the five steps to PLC Program development to our following programming example of a process mixer. The process mixer will be programmed using ladder logic. We will discuss each step of the PLC program development. 1 – Define the task: How does the process mixer work? A normally open start and normally … Read more
A data logger is also known as a data recorder or data acquisition. It is a method to record data over some time and events. The recorded information can come from sensors in the field. They can be digital or analog. Digital data can be used for counts, times, events (motor overload), etc. With the … Read more
Process control can be a bit intimidating. We will try and break down both On/Off and PID control in a fun way. This is a simple analogy without any math. On-Off Control Explained On/Off control can be used effectively with temperature control. Everyone’s house usually has a temperature controller that uses an On/Off control. The … Read more
A one-shot in the PLC will turn an output on for one scan. This is used to trigger events that should only happen once. An example of this would be to increment a value in memory. If a one-shot is not used, then every scan of the PLC will increment the value. What is a … Read more
A flip-flop circuit in a PLC usually has one input and two outputs. When the input is activated, the two outputs alternately latch on/off opposite each other. It is used to toggle (latch) work on and off with just one input. In the PLC, it is a single input that will toggle an output on … Read more
In part 1, we looked at writing PLC programs to control a traffic light using discrete bits and timed sequencing using indirect addressing. Part 2 used indirect addressing for inputs and output to control the program’s sequence of pneumatic (air) cylinders. Part 3 returned to the traffic light application and expanded our program significantly. We … Read more