Two simple ways to optimize your remote monitoring and alarm systems
System administrators rely on remote monitoring and alarm systems to provide around-the-clock updates for applications such as security, restricted access, power substations, and remote site management. Today's monitoring and data acquisition systems need to acquire information, such as temperature, humidity, door open/closed, and other I/O events, from local and remote sites to improve enterprise productivity. For large scale and remote applications, systems have become more distributed and rely heavily on Ethernet and IP-based networks. How remote I/O is implemented is a key factor that determines the efficiency of the monitoring system.
Adopting Active Ethernet I/O and an easy control logic are two simple ways system integrators can optimize the deployment of their remote monitoring and alarm systems.
Get active (Ethernet)
Two types of Ethernet I/O are currently available. Traditional PC-based Ethernet I/O, or passive remote I/O, is built on passive I/O devices that require instruction from a PC for operation. Active Ethernet I/O is based on self-directed operation of I/O devices, for automated status reporting and simple local control.
Passive Ethernet I/O
In passive Ethernet I/O systems, a host computer obtains data from I/O devices by continually scanning each device. For local area network environments, obtaining instant, or real-time, I/O status is possible only when devices are scanned very frequently. However, frequent scanning over the network results in high network overhead.
When I/O points are distributed throughout remote locations, response times cannot be guaranteed. This is a challenging situation for programmers if the timing of devices and readings is important to the application. Typically, timely I/O data measurement in this situation requires the installation of a separate host computer with physical proximity to the I/O devices. The on-site computer then forwards the data to a central host computer for actual processing.
Active Ethernet I/O
Active Ethernet I/O is a new concept for PC-based data acquisition and control that introduces proactive, condition-based reporting and control of I/O devices. Unlike traditional I/O servers, which are passive and must be polled for data, Active Ethernet I/O servers can automatically report and control I/O status based on user-specified conditions. This report-by-exception approach, new to PC-based I/O monitoring, requires far less bandwidth than traditional polling methods. Critical sensor data can be obtained immediately instead of being subject to polling intervals. This makes network communication between the host computer and Ethernet I/O server concise and efficient, and makes data transmission 20 times faster compared with traditional SCADA systems (50 ms compared to 1 sec).
This new Active Ethernet I/O architecture provides remote monitoring and alarm systems with the following useful benefits:
- Open standard TCP/IP and Ethernet
- Uses less bandwidth for bandwidth-critical applications
- Front-end intelligence reduces host loading
- 24/7 unmanned monitoring with multiple notification types
- Human-readable, detailed alarm descriptions
- Filters out most nuisance alarms
- Expansion capability for future scale-ups
Use simple logic
Even if you take advantage of Active Ethernet I/O technology for your system, you need an equally effective software architecture to control it. Most data acquisition, alarm messaging, and local control tasks require cumbersome programming and knowledge of C-language or PLC ladder. Choosing a remote I/O solution that can be configured using a simple control logic will not only save deployment time, effort, and cost, but also make the system easier to maintain and adapt.
For example, Moxa's patented Click&Go local control logic for the ioLogik E2000 series allows anyone familiar with IF-THEN-ELSE statements to control I/O channels and alarm messaging after a few simple steps. Intuitive IF-THEN-ELSE statements are used to specify conditions that are required for certain actions to take place. Up to three conditions, three IFs and their corresponding ELSEs, can be combined in rule. Supported actions include sending SNMP traps or TCP/UDP messages to up to 10 hosts at a time.
Click&Go can also be used to map an input channel on one Moxa ioLogik Active Ethernet I/O server to an output channel on another ioLogik for peer-to-peer I/O communication. Up to five different IP addresses can be entered as the output destination. Peer-to-peer I/O provides a very flexible and easy method of extending I/O signals or connecting remote on/off switches. It can be used, for example, to replace or extend the wiring of PLC or DCS systems over Ethernet.
Benefits of using Moxa's Active Ethernet I/O devices with Click&Go control logic include:
- Twenty-four IF-THEN-ELSE Programming Rules
- Local Monitoring and Local Control
- Remote Control
- Time-stamped Active Messaging
- Peer-to-peer I/O
Summary
Ethernet technology has the unique advantage of bi-directional communication, which has given rise in the IO industry to the so-called "push" and "pull" technologies. Active Ethernet I/O uses push technology to create a new type of remote monitoring and alarm system, which is particularly well-suited for applications that rarely experience exceptions. Using this technology is one way system integrators can optimize their remote monitoring and alarm systems since it frees up more bandwidth for data transmission. In addition, using an intuitive control logic, such as Moxa's proprietary Click&Go, will also make system programming and administration easier.
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