OPC stands for OLE for Process Control, but it should slightly be called COM for Process Control as OPC is depending on the COM> (Component Object Model). COM is the essential component operating systems of Windows and interplay controls between multiple components of software. The server of OPC suits similar to element of the operating system of Windows and is thus file names independently, locations of storage, and versions by using COM.
Many attempts was required to control the different vendors of hardware with software applications before OPC. There were many different protocols and systems; for every vendor and every protocol, a user must purchase special software to admittance the particular drivers and interfaces. User programs were thus in need of the system, protocol, or vendor. OPC on the foundation of DCOM or COM has the same and non-proprietary interface of software that has revolutionized data exchange in engineering of automation. Nowadays OPC is the mainly common method to swap over data between applications associated to systems real-time from different vendors.
Manufacturing Message Specification
MMS (Manufacturing Message Specification) is a messaging system international standard for exchanging data real-time and managerial control information between devices networked and/or applications Manufacturing Message Specification computer in a method that is autonomous of the appliance function being executed. MMS is an ISO 9506 standard that is built up and maintained by TC184, Industrial Automation for Standardization (ISO). The services of messaging given by MMS are common enough to be suitable for a large variety of devices, industries, and applications. For example, the service of MMS Read lets a device or application to interpret a variable from another device or application. Whether the device is a robot or a PLC, the services of MMS and messages are equal. Applications as dissimilar as fault annunciation, management of energy, handling of material, power distribution control of electrical, control of inventory, and positioning of deep space antenna in industries as various as aerospace, utility of electric, automotive, petrochemical, office machinery and etc.
The MMS offers a complete and flexible structure to swap over variable information through a network. The variable of MMS access model comprises capabilities for unnamed, named, and variables named lists. MMS also permits the description type of the variables to be controlled as a divide MMS object. The variables of MMS can be uncomplicated such as, floating point, string, integer, boolean, etc. or complex such as, structures and arrays.