eLinks are sophisticated, yet easy to configure and use, data acquisition and communications controllers designed to implement distributed monitoring and control systems over TCP/IP networks. Since Ethernet is the most widely used local area network, eLinks contain a built-in 100Base-T port.

eLink Controller

eLink controllers are housed in a rugged aluminum enclosure that is designed to be easily DIN-rail mounted in an equipment cabinet, "hub room," or other suitable enclosure. eLinks are powered from unregulated +10 to +30 Vdc and typically consume less than 1.5 watts. A small, wall-mounted power supply is provided with each eLink. The following is a picture of an eLink showing the size and location of I/O ports.

Architecture

eLinks are designed to minimize network traffic in data acquisition systems by only sending data when it changes. This is typically called "report by exception." Most other systems available today are scan-based and constantly poll the I/O over the network.

eLinks can be configured to buffer measurement data whenever the LAN goes down and automatically transfer it to CIMScan when communications is restored. Alarm condition can also be detected at the eLink and local personnel alerted to the problem.

The following is a diagram if the data flow within an eLink an its interface to CIMScan.

Available Configurations

eLink controllers are available in the following three basic configurations.

Distributed Data Acquisition

The firmware in this basic eLink is designed to interface our standard I/O Pods to control the monitoring and data acquisition within a building, an area, or a process.

SCADA System RTU This eLink controller version is similar to the above except it includes additional communications capabilities (Modbus) and provisions for local control.

Standard I/O

All eLink controllers contain the following I/O ports:

CIMScan PodNet interface for talking to multiple I/O Pod
Two (2) general purpose RS-232 serial ports
A 100Base-T Ethernet to interface with the CIMScan host
Alarm port (digital I/O)
RS-232 service port

The following diagram of a typical distributed system using eLinks:

Specifications

The following table contains the important specifications for the eLink controllers:

Operating Temp. Range	-40~70 °C
Relative Humidity	5-95%
Operating Voltage	10-30 Vdc
Maximum Power Required	1.5 W.
Memory & Clock	Battery Backed
RS-485 PodNet Ports	1
RS-232 Serial Ports	2
LAN Interface Port	100-Base-T
Primary Protocol	TCP/IP
Alternate Protocol	Modbus
Serial Expansion Ports	2
Digital I/O	3-In, 2-Out
Maximum Input Voltage	36 Vdc
Output Drive (open coll.)	750 ma.
Alarm Relay	SPDT
Indicators	4 LED

Capacities

eLink controllers have the following capacities:

Maximum number of I/O channels	256
Maximum number of I/O Pods supported	32
Fault buffer capacity	32,000 measurements
Maximum PodNet drop length	4,000 feet

Easy to Configure

eLink controllers are incredibly easy to configure with the supplied software that runs on any Windows-based laptop computer.