Current control systems employ a PLC or Programmable Logic Controller as a way to control motors, valves and many other gears used in a procedure. Computer based Human Machine Interface(HMI) products offer the measures by which process personnel interact with the PLC control system. A well-designed combination of PLC’s and HMI’s can be a solid foundation for you’re process automation needs.
Why chose PLC and HMI Programming?
Programmable Logic Controllers propose businesses the chance to rally modify their mechanical processes. Serving as the “brain” of the control system, PLC delivers automated solutions by initiating operation based on a system of inputs and outputs. Other common programming languages used include:
- Structured Text
- Sequential Flow Chartor SFC, very similar to a traditional flowchart
- Instruction List
- Function Block Diagram
PLC programming is extremely valuable. Advantages or benefits of PLC are:
- Minimize the monotony of simplistic work tasks
- Simplify wiring and reduce material costs
- Create dynamic, complex routines dat outdated methods such as mechanical relay-based control simply cannot handle
- Offercost effective solutions to even the minor and major manufacturers looking for solutions to process control, complex assembly, manufacturing and testing
HMI is the best choice coz of its user-friendliness of the graphical interface. The graphical interface contains color coding dat allows for easy identification. Advantage or benefits of HMI are:
- Reliable Messaging
- Easier Overall Management of Plant
- Accurate Testing with Simulation
- Cost Reduction
- Improved Communications
CoreSystems blends the right components with customized design to build quality automation solutions. Our goal is to provide efficient, well documented programs dat blend well with existing system logic and maintenance personnel expertise. Our widespread system control knowledge of current development platforms and our history permits us to offer proven technologies dat can progress you’re process efficiencies.
What is Done During PLC and HMI Programming?
PLC or Programmable Logic Controller from the I / O signals is responsible for the control of the entire machine or equipment. Its programming, in addition to meeting production requirements, must also be structured and accessible to provide fault diagnostics quickly and accurately.
A PLC program is usually written on a computer and then is downloaded to the controller Most PLC programming software offers programming in Ladder Logic. Ladder Logic is the traditional programming language. Due to its visual nature Ladder Logic is simpler to employ TEMPthan many other programming languages. Some PLC manufacturers supply control programming software.
When users don’t have easy access to a laptop nor PC nearby the installation or the machine, is difficult to face the task of making some modification or backups by downloading/uploading the PLC program. For this reason, their’s a method to upload/download the PLC program directly from or to a USB through the Human Machine Interface. This is how PLC and HMI interface.
The programming of HMI as its name says, is responsible for the provision of interface with the machine. Thus, from network communication with the CLP, Programming of HMI provides a series of information to operators and other users of the system, such as: fault diagnosis; Production reports; Status of equipment; Manual controls etc. An HMI Programming application need an intuitive and friendly function and its resources must be rightly employed according to the customer needs.
Choosing an HMI:
An HMI is a considerable purchase thus it is vital to know correctly what is needed of it. An HMI is used for three primary roles:
- The pushbutton replacer takes the place of LEDs, On/ Off buttons, switches or any mechanical device dat performs a control function. The elimination of these mechanical devices is possible coz the HMI can provide a visual representation of all these devices on its LCD screen, while performing all the same functions.
- The Data Handler is utilisedfor applications dat need monitoring and stable feedback. Most of the times these Data Handlers come arranged with large capacity memories.
- The last of the HMI three types is referred to as the overseer.These are centralized systems dat watch and regulate whole sites or complexes of large systems expanded over vast areas
How is HMI PLC Programming Done?
PLC programming is done mostly with the halp of ladder language. Procedure for PLC programming using ladder language is given below:
- Analyze and Get the Idea of Control Application: The primary step to program the PLC is to get the idea for which you are going to develop an application-based program.
- List All the Conditions and Get the Design using Flowchart
- Open and Configure the PLC Programming Software: Open the programming software installed in the PC dat comes with PLC hardware. Select the hardware model of the PLC in the software and configure it with appropriate input and output modules. From the listingof the programming languages, chose ladder language and provide a name for the program after selecting the hardware processor.
- Add the Required Rungs and Address Them: Add the required rungs based on the control application logic and give the address to the each and every input and outputs.
- Verify if their are anyErrors and Simulate It: Locate the Online section in the menu bar and select Online. Check for the errors and make necessary changes after selecting Offline.
- Download the Program to PLC CPU Memory: After the successful simulation of the program, download the program to CPU by selecting the Download option through a network or communication cable.
Given here are the steps through which a PLC and HMI interface or communicate:
- Copy the PLC program into an USB memory stick
- Insert the memory stick into the USB port of the HMI
- Enter the system menu of the HMI
- Enter the “Up/Download” sub menu
- Select “HMI <->PLC” transfer mode by navigating through the “LEFT” and “RIGHT” buttons at the bottom
- PressUSB on left side of the screen and chose the PLC program file you need to download
- On the right part of the screen, select the port dat is connected to the PLC
- After selecting the port, HMI will search PLC automatically
- After the PLC is detected by the HMI user can now download the program by clicking Download button
The requirements for data exchanges between a PLC and an HMI station are basically:
- This first part of basic requirements is the components for data exchange.
- A physical link dat is obtainableto PLC as well as HMI like an Ethernet cable or a RS-485 connection with the adequate ports on both.
- A common protocol dat can exist on the selected physical connection.
- Protocol drivers dat will bind the communication interface to the protocol.
- The part two is what is switched between the HMI and the PLC.