Uso de Mensaje de Textos para Controlar Sistemas SCADA
Use SMS Text Messages To Monitor & Control Your SCADA System
February 10, 2011
Trihedral has developed yet another supported option for their VTS HMI software to securely communicate with and access data from remote locations.
SMS, or short message service, is the text-based communication protocol used by the majority of mobile phone networks worldwide. Trihedral’s Phoenix SMS I/O Driver captures data from field devices in the form of text messages using the SMS protocol. The driver sends and receives these messages through a central GPRS/GSM modem.
South Carolina integrator Collins Controls, Inc. installed the first Phoenix SMS I/O Driver at Valley Public Service Authority, South Carolina in November 2010. Company President Gary Collins is pleased with its performance so far. “It allows your SCADA system to monitor and control low lying sites that you couldn’t reach with licensed or spread spectrum radios,” says Collins. “In some cases you would need a 100 foot radio tower to reach these places which would incur higher installation cost. Plus, you don’t have to worry about radio path studies, repeaters, weather conditions, foliage or any of the other things that can cause you headaches with radio networks. So long as you have cellular telephone access you don’t need to maintain any other infrastructure.”
How it Works
The driver was written specifically to interface to a Phoenix Contact PSI-GPRS/GSM-MODEM/RS232-QB central modem using the Phoenix Contact PSI-MODEM-SMS-REL RTU as the remote I/O device. It allows authorized users to send text messages that query these devices for information and issue commands to do things like start pumps or close valves or capture alarm. The driver processes data from unsolicited messages from an RTU or by polling it. Unsolicited messages received are identified by the RTU phone number and sent to the appropriate tags in VTS.
When an RTU is polled, a text message asks the unit for its I/O status. Return text messages are processed the same as unsolicited messages. RTUs can be configured to report a change of state with a text message and include the current status of the RTU I/O with every message. This configuration minimizes air time and reduces cellular costs. The poll interval configured in either the I/O tags or the polling driver will determine the frequency at which the RTU is polled for data.
The central modem uses a VTS “Plug-In” module which handles the specifics of sending and receiving text messages for this model. This is done because the AT command set for handling text messages differs between modem manufacturers. The remainder of the driver is a common path for linking RTU I/O to VTS tags.
VTS software already includes an extensive library of drivers that allow it to monitor and control hundreds of different kinds of I/O devices including remote telemetry units, programmable logic controllers and pump controllers. Other VTS drivers provide a wide variety of communication options including Serial, Ethernet, OPC, ODBC and SNMP. VTS users can also use the integrated VTS WAP Server to access their applications using their WAP-enabled smart phones and mobile devices.
VTS© is Windows-based monitoring & control software for mission-critical applications in numerous industries. These range from OEM machine interfaces and standalone workstations to large, distributed client/server systems. Trihedral is recognized as a leading manufacturer of software for HMI / SCADA applications. The worldwide appeal of our products is demonstrated by a large and satisfied customer base spanning six continents.
SOURCE: Trihedral Engineering Limited and Water Online News.