Blog of motion control, electrical machinery, automation, process control, motor control, green energy...

Common control functions include:

Velocity control.
Position (point-to-point) control: There are several methods for computing a motion trajectory. These are often based on the velocity profiles of a move such as a triangular profile, trapezoidal profile, or an S-curve profile.
Pressure or Force control.
Trans-mutational vector mapping.
Electronic gearing (or cam profiling):

The basic architecture of a motion control system contains:

A motion controller to generate set points (the desired output or motion profile) and close a position and/or velocity feedback loop.

A drive or amplifier to transform the control signal from the motion controller into a higher power electrical current or voltage that is presented to the actuator. Newer "intelligent" drives can close the position and velocity loops internally, resulting in much more accurate control.

An actuator, such as a hydraulic pump, air cylinder, linear actuator, or electric motor for output motion.

CAN (Can Bus) is a message based protocol, designed specifically for automotive applications but now also used in other areas such as industrial automation and medical equipment.

Controller area network (CAN, CAN-bus) development started originally in 1983 at Robert Bosch GmbH. This message based protocol was officially released in 1986 at the Society of Automotive Engineers (SAE) congress in Detroit, Michigan. The first CAN controller chips, produced by Intel and Philips, came on the market in 1987. And Bosch published the CAN 2.0 specification in 1991.

Controller area network (CAN, CAN-bus) is one of five protocols used in the OBD-II vehicle diagnostics standard. The OBD standard has been mandatory for all cars and light trucks sold in the United States since 1996, and the EOBD standard, mandatory for all petrol vehicles sold in the European Union since 2001 and all diesel vehicles since 2004.

Users can combine varieties of Profibus protocols with their own software and other requirements, resulting in a unique application profile. There are many application profiles that combine standards for transmission media, communication protocol (FMS, DP-V0, etc), and unique protocols. Each application profile is tailored to a specific use.

Two application profiles of Profibus are widespread, PROFIsafe and PROFIdrive.

PROFIsafe uses additional software to create a high-integrity network. This network is useful in situations where high safety is a requirement. Suppliers and manufacturers must maintain high standards in quality to be certified in PROFIsafe.

ProfiBus DP
This type of ProfiBus is more universal, called ProfiBus DP (Decentralized Periphery). ProfiBus DP (Decentralized Periphery) is much simpler and faster. ProfiBus DP is used in the overwhelming majority of ProfiBus application profiles in the industry today. Application profiles allow users to combine their requirements for a specific solution.

ProfiBus DP has three separate versions. Each version of ProfiBus DP, from DP-V0 to DP-V1 and DP-V2, provides some newer, more complicated features.

ProfiBus PA
ProfiBus PA is a protocol designed for Process Automation. In fact ProfiBus PA is a type of ProfiBus DP Application profile. ProfiBus PA standardizes the process of transmitting measured data. But it does hold a very important unique characteristic. ProfiBus PA was designed specifically for use in hazardous environments.

The initial version of ProfiBus was ProfiBus FMS, Fieldbus Message Specification. ProfiBus FMS was designed to communicate between Programmable Logic Controllers (PLCs) and PCs, sending complex information between them. Unfortunately, as the initial effort of ProfiBus designers, the FMS technology was not as flexible as needed. ProfiBus FMS was not appropriate for less complex messages, also inappropriate for communication on a wider, more complicated network. New types of ProfiBus would satisfy those needs.

Profibus PA (Process Automation) is used to monitor measuring equipment via a process control system in process automation applications.

Profibus PA (Process Automation) is designed for use in explosion/hazardous areas (Ex-zone 0 and 1). The Physical Layer (i.e. the cable) conforms to IEC 61158-2, which allows power to be delivered over the bus to field instruments, while limiting current flows so that explosive conditions are not created, even if a malfunction occurs. The number of devices attached to a PA (Process Automation) segment is limited by this feature. PA (Process Automation) has a data transmission rate of 31.25 kbit/s. But PA (Process Automation) uses the same protocol as DP (Decentralized Peripherals), and can be linked to a DP (Decentralized Peripherals) network using a coupler device. The much faster DP (Decentralized Peripherals) acts as a backbone network for transmitting process signals to the controller.

Profibus (Process Field Bus) is a variety of protocols, which is built on the same field-bus technology bundle.

There are two variations of Profibus (Process Field Bus) in use today. The most commonly used one is Profibus DP (Decentralized Peripherals), and the lesser used one is application specific, Profibus PA (Process Automation).

Below are simple descriptions for these 2 variations of Profibus.

Profibus DP (Decentralized Peripherals) is a protocol made for (deterministic) communication between Profibus masters and their remote I/O slaves. PROFIBUS DP (Decentralized Peripherals) is used to operate sensors and actuators via a centralized controller in production (factory) automation applications. This variantion is mostly applied. (to be continued)

PLC control:

Disadvantages of Programmable logic controller (PLC, programmable controller) control
1 There's too much work required in connecting wires.
2 There's difficulty with changes or replacements.
3 It's always difficult to find errors; And require skillful work force.
4 When a problem occurs, hold-up time is indefinite, usually long.

Advantages of Programmable logic controller (PLC) control
 

A programmable logic controller (PLC), sometimes called as programmable controller, is an industrial computer used to monitor inputs, and depending upon their state make decisions based on its program or logic, to control (turn on/off) its outputs to automate a machine or a process. That means the programmable logic controller (PLC) is used for automation of electromechanical processes, such as control of machinery on factory assembly lines, amusement rides, or lighting fixtures.

Programmable logic controllers (PLCs, programmable controllers) are used in many industries and machines. The programmable logic controller (PLC) is not like the general-purpose computer