ÖVE/ÖNORM EN 61158-4

The Fieldbus Data Link Layer provides basic time-critical messaging communications between devices in an automation environment. The purpose of this part of IEC 61158 is to define eight distinct and non-interoperable fieldbus Data Link protocols. Each protocol defined in this part of this standard is most closely related to, and lies within the field of application of, the corresponding services of IEC 61158-3, the fieldbus Data Link Service Definition. The eight distinct protocols are the following: Type 1 A DL-protocol for the Type 1 DL-service. The maximum system size is 56k links of 232 nodes, each with 240 DLSAP-addresses and related peer and publisher DLCEPs, plus another 768 link-wide group DL-addresses per link, plus another 256 DLSAP-addresses and 2816 peer and publisher DLCEPs per link which can be allocated among the link s nodes, plus 227 group DL-addresses for the extended link. Fewer links or nodes permits an increase in the number of DLSAP-addresses and related DLCEPs. Type 2 A DL-protocol for the Type 2 DL-service. The maximum system size is an unlimited number of links of 99 nodes, each with 255 DLSAP-addresses. Each link has a maximum of 224 related peer and publisher DLCEPs. Type 3 A DL-protocol for the Type 3 DL-service. The maximum system size is an unlimited number of links of 127 nodes, each with 66 DLSAP-addresses. Type 4 A DL-protocol for the Type 4 DL-service. The maximum system size is a single link with a virtually unlimited number of nodes, each with 256 DLSAP-addresses connected to a single DLS-user. Type 5 A second DL-protocol for the Type 1 DL-service. The maximum system size for this protocol is 240 links of 240 nodes, each with 216 DLSAP-addresses and related peer and publisher DLCEPs, plus another 227 link-wide group DL-addresses per link, plus 227 group DL-addresses for the extended link. A normative specification of this protocol was not available at t (...abbreviated)