ACC Automation: PLC & Industrial Control Learning
Practical Tips and Techniques
We will create a simple and inexpensive analog voltage tester for a PLC using a potentiometer and a 9VDC battery. The potentiometer will be 5K ohms. This should be enough impedance for most analog inputs of the programmable logic controller. (PLC) Voltage impedance for analog voltage inputs is in the megaohm range where the current … Read more
We will look at a PLC programming example of delaying the start of 7 motors. Each motor will be on a switch that the operator can select at any time. The motor outputs should have a 5-second delay between the outputs coming on. This question originally came from PLCTalk.net. An original solution to the problem … Read more
We will continue the series by looking at a sequencer controlling seven cylinders that can be taught. The cylinders can be operator programmed from the AdvancedHMI screen. You will be able to select what cylinders to activate at each step and program in 500 steps. Our PLC will be the Do-More from Automation Direct. Here … Read more
I have been recently asked how you can move data conditionally on an excel spreadsheet once the information has been obtained from the PLC? Monthly data was being collected from the PLC and put on an excel spreadsheet using Omron CX-Server DDE. They wanted at the beginning of each month to move the data to … Read more
We will use VBA in Excel to communicate to an Omron PLC. This will use the serial host link protocol. ACC Omron Host Link VBA In Part 1, we used VB6 to communicate from the computer to the PLC (Host Link Protocol). We will now use Visual Basic for Applications (VBA) to accomplish the same … 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
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. We will now return to the traffic light application and expand our program significantly. … Read more
The hostlink communication protocol is a method developed by Omron for communication to PLCs and other equipment. This ASCII-based protocol is used over RS232 or RS422/RS485. It is a many-to-one implementation, meaning you can communicate with up to 32 devices back to a master. (1: N) This communication on the industrial floor can control PLCs, Temperature … Read more