Data logging: Trolley museum controls rectifiers remotely
The nonprofit Pennsylvania Trolley Museum (PTM) keeps historic trolley lines running with two 500 kW 600 Vdc trolley rectifiers at its East Site, a small booster at its West Site, and more than 100 volunteers. What PTM was missing, however, was a practical way to keep these sites—which are 3,500 ft apart—in constant communication.
The nonprofit Pennsylvania Trolley Museum (PTM) keeps historic trolley lines running with two 500 kW 600 Vdc trolley rectifiers at its East Site, a small booster at its West Site, and more than 100 volunteers. What PTM was missing, however, was a practical way to keep these sites—which are 3,500 ft apart—in constant communication. Donated data loggers from Red Lion provide monitoring, notification, and logging options, as well as multiple protocol conversion and a built-in Web server.
The museum’s application offered several unique requirements:
Remote control of the East Site rectifiers at the West Site.
The ability for the dispatcher to view in real time the current power demand to avoid setting a costly “super peak.”
A means to data log the demand intervals (15 minute) and the operations of the rectifier breakers.
A way to notify offsite volunteers that the electrical system has a problem.
The ability to keep the PLC clocks accurate over a long period of time.
A solution that was cost-effective, reliable, and simple to implement and program.
To control trolley rectifiers remotely, the museum considered purchasing one of several dedicated rectifier control devices on the market, but the price tag of more than $9,000 per unit was too costly for the nonprofit. Even at this price, however, the devices did not have sufficient capability without additional software. Less expensive PLCs also were considered, but these also fell outside PTM’s budget range and failed to offer the necessary options.
Red Lion donated a Data Station Plus so volunteers could keep the historic site running. The device provides a virtual HMI with built-in PC-based SCADA functionality (DSPSX & DSPGT) for remote control and monitoring of sites and power usage. Data logging is done directly to CSV files on CompactFlash cards.
The device sends alarm messages to volunteer engineers via e-mail or text message. The unit receives and maintains accurate times from an Internet time source via the SNTP (simple network time protocol) client facility, while the Webserver provides worldwide access to data logs. According to Red Lion, 10 Base-T/100 Base-TX Ethernet connection can connect to an unlimited number of devices via four protocols simultaneously, and independent serial ports provide virtually unlimited integration methods. Extensive built-in drivers provide data mapping to PLCs, PCs, and SCADA systems.
Red Lion’s donation also included a development kit containing its Crimson 2.0 software for simple programming and implementation of the equipment. A Red Lion brochure on the Data Station Plus, available in three models (DSPLE, DSPSX, and DSPGT), is newly available. www.redlion.com
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