Chapter 2 Operation; Description - Contemporary Controls Metasys JC-MER-CXB User Manual

2
Operation

Description

The JC-MER-CXB integrates Metasys N1 LAN segments with an
Ethernet network that uses the TCP/IP (Transmission Control
Protocol/Internet Protocol) suite. The router provides the physical
connection between a Metasys ARCNET segment and the Ethernet
network. It takes advantage of a customer's existing Ethernet
network, while maintaining the dedicated Facility Management
System (FMS) communications necessary for complex, time-critical,
local control strategies.
With the JC-MER-CXB, Metasys controllers communicate transparently
over Ethernet, using standard components and maintaining complete
compatibility with existing network equipment. From an operator's
view, this coupling of the N1 LAN to Ethernet creates a single large
network. No special commands are necessary to switch between
networks; data automatically transmits between networks without
operator knowledge or intervention.
The JC-MER-CXB communicates over an Ethernet network using the
TCP/IP protocol. Two networked JC-MER-CXBs pass ARCNET
data between themselves using the User Datagram Protocol (UDP)
service provided by TCP/IP. On the Ethernet network, the router is
seen as a workstation passing messages to another workstation. If a
power failure occurs, the router automatically restarts communications
once power is restored.
The JC-MER-CXB is derived from an earlier version of this device that
was an expansion module that occupied two slots of a Contemporary
Controls MOD HUB ARCNET Modular Active Hub. The new device
can be powered from an available low-voltage source or with an
optional wall-mount transformer. The ARCNET and the Ethernet
connections are made through ports on the front panel of the device.
Unlike a PMI/OWS, the JC-MER-CXB has no monitor or keyboard.
Instead, the monitor/keyboard functionality is done by an external
laptop or desktop computer running a terminal emulation program (like
HyperTerminal), while connected to COM ports on the JC-MER-CXB.
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