Create an Analog Voltage Input Tester for a PLC

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 are in the mega ohm range where current input is typically 250 ohms. Our tester will be for analog voltage inputs (0-10 VDC). Check your input specifications before wiring anything to your PLC. I have used this tester for other voltage inputs along with a meter to ensure that the voltage levels do not get out of range for the input signal.
Analog inputs to the PLC are continuous and can come in a variety of signals. These signals can come from temperature, flow rate, pressure, distance, etc. Continue Reading!

Omron CP1H Compare Instructions

Just about every program usually has some data comparison instruction. This is the ability to compare information from one area of the controller to another and act on results. The Omron CP1H series of programmable logic controllers provide several different ways to compare information. We will be looking at several different ways in which we can do this with some programming examples. Sometimes the instruction used for data comparison in the Omron CP1H will determine the kind of data that we are comparing. You must look at the individual instructions to determine if this is the case or not. Continue Reading!

Wiring Interposing Relays

Interposing relay means a device that will separate two different circuits. The isolation can be for current consumption, voltage differences, voltage references or a combination of both current and voltage. We can use these relays to help connect our inputs and outputs on our programmable logic controller. (PLC) Continue Reading!

Omron CP1H Data Movement

Every program usually has some kind of data movement. This is the ability to transfer information from one area of the controller to another. The Omron CP1H series of programmable logic controllers provide several different ways to manipulate this information. We will be looking at several different ways in which data movement can happen with some programming examples. Data movement in the Omron CP1H does not care what is in the bits that make up the word. It will just send or receive this information. Remember that it is usually the instruction used, that determines how the information in the memory is determined. Continue Reading!

Omron CP1H Counters

The Omron CP1H series of programmable logic controllers are capable of having 4096 basic counters. There are two basic counter instructions in the PLC. Each of basic instructions can be either binary or BCD. The memory area for counters have separate areas for the Counter PVs (Present values) and the Counter Completion Flags. We will be looking at the basic Counter instructions in the CP1H along with some programming examples. Continue Reading!