Delta RMC151 - Manual (Page 445)

6 Communication
Each protocol is briefly described below:
ARP (Address Resolution Protocol)
Ethernet packets can either be broadcast (received by all devices on the network) or sent
to a single MAC address. However, applications generally address computers by IP
address rather than MAC address. Therefore, this protocol is used to determine the MAC
address of the computer owning a given IP address.
BOOTP (BOOTstrap Protocol)
This protocol is used to allow a central database to be maintained with all IP addresses on
a network. This single computer is the BOOTP server. When a BOOTP client (such as the
RMC, if configured to use BOOTP) starts up, it broadcasts asking a BOOTP server to tell it
what its IP address should be. The BOOTP server looks up the MAC address of the BOOTP
client in a database and sends a reply with the corresponding IP address.
When the RMC powers up, it broadcasts a request for its IP parameters. If a BOOTP
server is available on the network, then the BOOTP server will look into a database of
mappings from MAC addresses to IP addresses for the MAC address of the RMC that sent
the request. If it finds a match, it will give the RMC an IP address, default gateway, and
subnet mask. If no BOOTP server responds—either because no BOOTP server exists, or
the RMC's MAC address was not found in the BOOTP server's database—the RMC's
Ethernet communication channel will not be usable.
CIP (Control Information Protocol)
See the EtherNet/IP section below.
CSP (Client/Server Protocol)
This is a proprietary protocol developed by Allen-Bradley, Inc. Variants of this are used on
Allen-Bradley's SLC 5/05 and PLC-5 controllers. This protocol is also used by the Allen-
Bradley's SoftLogix 5 and RSLinx and SoftPLC Corporation's SoftPLC. Allen-Bradley does
not publish the specifications for this protocol. See the CSP topic for details on usage with
the RMC.
DHCP (Dynamic Host Configuration Protocol)
This protocol is an enhanced version of BOOTP. However, for industrial applications, the
enhancements (lease times and dynamic assignment of IP addresses) are generally not
usable. The RMC75E and RMC150E support both BOOTP and DHCP so that the user may
use either type of server.
DMCP (Delta Motion Control Protocol)
A simple Ethernet protocol intended for use with direct communication to the RMC75E
and RMC150E over TCP or UDP. In applications where none of the RMC’s other protocols
are supported by the master controller, but direct communication over TCP or UDP is
allowed, Delta recommends that the DMCP protocol be implemented by the user
manually.
Ethernet II
This is the most common framing layer protocol used by Ethernet devices. Other
alternatives include IEEE 802.3 SNAP, IEEE 802.5 (Token Ring), and IEEE 802.4 (Token
Bus). The RMC only supports Ethernet II framing, and therefore will not work on
networks using any of the other framing types. All PLCs currently support Ethernet II
framing although the Modicon Quantum allows selecting either Ethernet II (the default) or
IEEE 802.3 SNAP.
EtherNet/IP
This is an open application protocol, originally developed by Allen-Bradley, Inc., but now
maintained and distributed by ODVA (http://www.odva.org). The specification and
source code are available through http://www.ethernet-ip.org. This protocol is an
Ethernet-adaptation of the Control Information Protocol (CIP) in the same way that
DeviceNet is a CAN adaptation of CIP and ControlNet is a CTDMA-adaptation of
CIP. EtherNet/IP is used by the Allen Bradley ControlLogix's Ethernet modules (1756-
deltamotion.com 425