Basically, the function of a watchdog timer is to make sure that some processing malfunction does not shut down the entire system. Examples of malfunctions can be hardware failures or a program error that may, for instance, send the program into an infinite loop. In PLCs, watchdog timers are typically involved with the program scan […]
PLCs + PACs
What’s to know about analog and digital I/O for PLCs?
Common PLC input/output (I/O) can be analog and/or digital. An analog signal is one whose value continually varies over time. They are best represented as a continuous signal like a sine wave. Each point on the wave has a precisely defined value. For example, analog inputs for PLCs can include signals from pressure transducers and […]
Current state of programmable automation controllers (PACs) for motion
Programmable automation controllers (PACs) excel in commanding complex automation setups that involve PC-based and HMI functions as well as process control (largely because of the way they handle I/O). PACs are also increasingly common in motion applications for machining or handling discrete product thanks to the flexibility and interoperability they offer machine designs. Today’s PACs […]
What are Instruction Lists (ILs) for PLC programming?
Instruction lists (or ILs) are one of the five PLC programming languages defined by the IEC 61131-3 standard. (The others being ladder logic diagrams, function block diagrams, sequential function charts, and structured text.) ILs are not a graphical programming language. Instead, they most resemble assembly language programming. As the name implies, a program is a […]
Parker Hannifin now offers new PAC Terminal (PT) thin-client HMI
Parker’s Electromechanical and Drives Division – North America now offers the PAC Terminal (PT) thin-client HMI. The PT is a thin-client HMI developed to work seamlessly with the Parker Automation Controller (PAC). With the PAC handling the control and HMI logic, the PT is responsible for displaying the embedded HMI as well as sending touch […]
What do programmable automation controller (PAC) add-on modules do?
By Steve Meyer || Programmable automation controllers (PACs) are largely architected as traditional programmable logic controllers (PLCs) to reliably execute control programs. The major difference (from an electronics standpoint) is how PACs have a high-bandwidth backplane that: Allows integration of different architectures Allows additional processors to augment the functionality of the primary PAC. While there’s […]
What do USB data-logging ports do on programmable automation controllers (PACs)?
By Steve Meyer || Data logging (and use of that data later) was once a complicated venture possible only through specialty hardware and applications — often in the form of standalone supervisory control and data acquisition or SCADA systems. Even new software and PC-based systems come at significant cost. In contrast, many of today’s programmable […]
What are DCS, RTU, PLC, and PC functions on programmable automation controllers?
By Steve Meyer || Distributed control systems (DCSs), remote terminal units (RTUs), and programmable logic controllers (PLCs) are control systems with hardware and programming designed to meet the requirements of specific applications. Today’s programmable automation controller (PAC) hardware runs DCS, RTU, PLC, and PC functions as software to replicate the legacy hardware that’s operated in […]
Parker Hannifin Corp. launches Parker Automation Manager 1.3 — an IDE for PAC programming
Parker’s Electromechanical and Drives Division – North America has just released the Parker Automation Manager (PAM) 1.3 — an update that significantly expands Parker Automation Controller (PAC) features and functionality, allowing users to integrate complex robotics into their machine controller in an easy-to-use, graphical environment. While the PAC is Parker’s all-in-one machine controls solution that combines PLC, HMI, […]
What are sequential function charts (SFCs) for PLCs?
Sequential function charts (or SFCs) are one of the five PLC programming languages defined by the IEC 61131-3 standard. (The others being ladder logic diagrams, function block diagrams, structured text and instruction lists.) SFCs are a graphical programming language, not text-based. Being a visual programming language means that it’s well suited to the task of […]
