I recently received a question on PNP and NPN sensors. They wanted an explanation of what a sink is and how to wire one. Confusion over the Normally Open and Normally Closed function of the sensor is also a common question. Several diagrams will show a resistor attached to the blue wire and a load across the others, what does it all mean?
It is quite confusing sometimes the language we use for these devices. Sometimes it is the way we talk about the sensor and sometimes about the device we are connecting. (PLC)
We will break it down and go over the wiring to a PLC input. Let’s get started. Continue Reading!
Signal conditioners are used with analog current and voltage signals. They have the ability to change your input analog signal to another output analog signal. As an example, we can have 4-20mA analog input and change it to a 0-10VDC output signal so we can wire this into our PLC. Typically signal conditioners will also electrically isolate the input and output signals. This is either done by magnetic or optical isolation. You would usually specify the input and output signals that are required in your circuit to choose the signal conditioner required. Using a universal signal conditioner will take a variety of signals and is a great product to use in troubleshooting analog circuits.
We will be using a universal signal conditioner to convert a thermocouple temperature input into a 0-10VDC linear output. This will be wired into the analog card of the Click PLC.
Let’s get started. Continue Reading!
An ultrasonic sensor (switch) is able to detect object presence without physical contact (limit switch). No physical contact means that the switch has no parts that will wear out. The life span of the sensor is increased with less maintenance.
An ultrasonic sensor will use sound waves to detect objects. These sound waves are at a level that we cannot hear. Distance is measured by the time it takes to send and receive the ultrasonic wave. Objects can be measured the same no matter what the colour, transparency, shininess, or lighting conditions of the application.
We will be wiring an ultrasonic sensor into the input of our Click PLC. This will include a discrete and analog input signal. The UK1F-E7-0A is an 18mm diameter sensor that has a PNP N.O./N.C. selectable output with analog output of 0 -10 VDC. The sensing distance is 200mm to 2200mm and has a one-hertz switching capacity. A 4-pin M12 quick disconnect is available but we will be wiring in our 2m wired version. Let’s get started. Continue Reading!
A proximity sensor (switch) is able to detect object presence without physical contact like a limit switch. No physical contact means that the switch has no parts that will wear out. The life span of the sensor is increased with less maintenance.
A capacitive proximity sensor will detect ferrous and non-ferrous objects. The sensor works by oscillating the charge on the plates in the sensor. When an object is placed in front of the surface, the amount of current flow is detected. (Capacitance) The dielectric of objects will determine the distance that the object can be detected.
We will be wiring a capacitive proximity switch into the input of our Click PLC. The CK1-00-2H is an 18mm diameter, NPN/PNP N.O./N.C. selectable output with a 12mm sensing distance. That means that the sensor can be wired as positive (Sourcing) or negative (Sinking) switch. This unshielded 10 Hz switching frequency sensor also has a 4-pin M12 quick disconnect. Let’s get started. Continue Reading!
A push button (pushbutton) is a simple human interface for controlling some aspect of a machine or process. The push button requires a force to push the button to change the electrical operation from off to on or vice versa. The condition of the output is usually momentarily. Some common everyday pushbuttons we use are keyboards keys.
A selector switch is also a mechanical device that will require a force to turn the electrical operation from off to on or vice versa. The selector switch usually locks into a position.
We will be wiring two illuminated pushbutton switches into our Click PLC. A selector switch will also be wired in. Let’s get started. Continue Reading!
The Productivity 1000 series of programmable logic controllers has a slim stackable super compact design. This is sometimes also referred to as a shoebox PLC because of the shape and way in which expansion modules are added. This new Productivity 1000 series PLC is the latest in the Productivity series of controllers that have hit the market.
Productivity 1000 (Stackable Micro PLC)
Productivity 2000 (Micro Modular Programmable Controller)
Productivity 3000 (Modular Programmable Controller)
The Productivity 1000 series PLC provides the following features for your automation control panel.
– 50MB user memory – Can handle very complex applications easily.
– 4 built-in communication ports – Easy connectivity to your network. This would include your PC, HMI, Networks, etc.
– Data logging up to 32 GB on a microSD card
– Add up to 15 IO modules to communicate to your field sensors.
– Free Software and 30 days of free training with every CPU from Automation Direct.
– Interactive PLC Configuration Tool
– Tag Names
– Auto-discovery IO – Physical I/O tags will be generated based on each module’s position in the base. You can also reconfigure the setup and assign new tags manually.
– I/O Modules have QR codes under the wiring cover. This can be scanned so you can have the latest specifications/wiring diagrams for the module.
– Limitless PID – Autotuning – Individual or Cascade Mode – etc
– Web Server and Mobile Access
– Advanced Software instruction set
We will be looking at a lot of these features of this powerful controller. Let’s start by looking at the hardware. Continue Reading!
Advanced HMI is a powerful, adaptable HMI/SCADA (Supervisory Control and Data Acquisition) development package that takes advantage of Visual Studio. There is no coding required and you can simply drag and drop items onto the page. The best thing is that the software is free. We will look at using AdvancedHMI with the Omron CP1H PLC.
Our sample CP1H PLC program will use button and indicators to control a start/stop jog circuit. An analog input into the PLC will be scaled and displayed on a gauge on our AdvancedHMI screen. We will also write information to our 7 segment display on the CPU from our AdvancedHMI screen. This communication will be done using Omron serial host link protocol over a RS485 serial cable. The AdvancedHMI package will run on a windows PC and communicate out the port using a USB to RS485 adapter. Let’s get started. Continue Reading!
The data control instructions in the Omron CP1H programmable logic controller are used to manipulate the outputs based upon control conditions. Control is the main purpose of these instructions within the PLC. Instructions include PID (Proportional, Integral and Derivative), PID with Auto tuning, Dead Band Control, Limit, Dead Zone Control, Time Proportional Output, Scaling, etc.
We will be looking at some of these instructions in the Omron CP1H PLC. Examples of the instructions will be presented. Continue Reading!
The Omron CP1H programmable logic controller has several different table data processing instructions. These instructions are used to handle table data, stacks and other ranges of data.
We can define a stack of data. With this data we can then do the following: add new data by pushing onto the stack, use FIFO (First In First Out), use LIFO (Last In First Out), find the current stack size and read, overwrite, insert or delete from the stack.
Dimension record tables are used to define the length of each record and the number of records. We can then write and read these records. This is ideal for data acquisition projects.
Other instructions found in the table data processing instructions include searching, summing and finding minimum and maximum values.
We will be looking at these instructions in the Omron CP1H PLC. Examples of the instructions will be presented. Continue Reading!
Programmable logic controller programming is all about manipulating the bits within the memory of the controller. Sometimes we need to convert from one form to another. This is where we will use data conversion instructions. BCD to Binary, Line to Column, Grey Scale and Multiplexing are just some of the data conversion instructions. We will be looking at some of these instructions in the Omron CP1H PLC. Examples of some of the instructions will be presented. Continue Reading!