The basics of MMS (Manufacturing Message Specification, ISO 9506) and ASN.1 (Abstract Syntax Notation 1) are available at the NettedAutomation Website.
MMS is a messaging system for modeling real devices and functions and for exchanging information about the real device, and exchanging process data - under real-time conditions - and supervisory control information between networked devices and/or computer applications. MMS is an international standard (ISO 9506) that has been developed and maintained by the ISO Technical Committee 184 (TC184) - Industrial Automation - of the International Organization for Standardization (ISO).
The object models and messaging services provided by MMS are generic enough to be appropriate for a wide variety of devices, applications, and industries. Whether the device is a Programmable Logic Controller (PLC) or a robot, the MMS object models, services and messages are identical. Similarly, applications as diverse as material handling, fault annunciation, energy management, electrical power distribution control, inventory control, and deep space antenna positioning in industries as varied as automotive, aerospace, petro-chemical, electric utility, office machinery and space exploration have put MMS to useful work.
MMS is the base standard to communicate all client/server information exchange for IEC 61850, IEC 61400-25 (in addition to other protocols) and IEC 60870-6 TASE.2 (ICCP). ASN.1 is used in MMS to specify the syntax of messages, ASN.1 BER defines the concrete encoding of the messages. Please note that only a small subset of MMS and ASN.1 is needed by IEC 61850, IEC 61400-25 and TASE.2.
Click HERE to begin the Tutorial ... enjoy.