Is a PLC HMI Combo Unit Better than Separate Systems?
The combination of PLC processing and HMI monitoring and control into a single platform has become popular these days. Previously, separate PLC and HMI devices connected to each other was the standard system for machine automation. Both the systems have their perks and drawbacks, but a PLC HMI combo is more available and popular nowadays.
Definitions of PLC and HMI
PLC or a programmable logic controller works as a digital computer to control the manufacturing processes. They are highly reliable automation controllers that are capable of providing a high level of control and programming along with handling fault diagnosis. Their first use in the automobile industry was as an alternative to hard-wired relays and timers.
An HMI or Human Machine Interface allows a PLC to interact with the human operator for regular control, alarm reporting, or configuration. Also known as graphical user interfaces (GUIs) and man-machine interfaces (MMIs), the system uses buttons, lights, and sometimes texts and digital touch screens to interact with the operator.
Is a PLC HMI Combo Unit Better Option?
A PLC HMI combination has certain edges over the separate HMI interface with PLC system in terms of hardware and software effectiveness. Let’s take a look if a combo system is better than different systems working together:
A combined unit is more like an HMI with built-in PLC system. So, it takes less space and minimizes wiring than separate units because it uses one single power source and network connection for both the units.
On the other hand, separate systems have a larger memory capacity though more advanced PLC HMI combo units are not far behind with improved data storage and math functions.
A combined unit uses a single suite of software, which makes it easier to operate and run the system. Separate systems, on the contrary, work like two isolated programs that are integrated together with configuration software.
As the industries have been using separate PLC and HMI systems from the beginning, it’s easier to find a full range of connection options for them. Most of the manufacturers produce a wide array of I/O, communication, and device integration for separate systems.
PLC HMI combo systems also have connection options suitable for many applications the range is limited compared to separate systems.
A PLC HMI combination offers a cost-effective solution for small machines and systems, especially if the application systems don’t require a great variety of I/O and high-end functions. Besides, a combo unit minimizes labor costs too as it demands less development time.
A combo system is useful for applying in packaging equipment, small OEM machines, small-scale process skids in gas and oil, remote wells, refrigeration equipment, simple pump control, and more.
Separate systems are more suitable for complex machine applications. They can better handle the robotic program, communication to vision framework, and the precision motion required by the multiple motion control axes of sophisticated devices.
Both the PLC HMI combo units and separate systems have their strong points. The separate units are useful for complex and a wide variety of applications because of the availability of a full range configuration and processions options. However, a combined system is cost-efficient and is better for small equipment and processes.