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Replace Dial-Up Modems for SCADA Systems

A natural gas utility had been using analog dial-up modems to collect data from Remote Terminal Units (RTUs) located on a pipeline. The RTUs communicated data from devices such as flow meters and pressure meters to the SCADA host system via analog dial-up modem.

This solution required one modem in the centralized control room and another modem for each RTU along the pipeline. While this solution effectively collected and transmitted the data, the utility incurred a high fixed monthly recurring cost for modems with low data usage.

The utility replaced the analog modems with the PortServer® TS Haz MEI, a serial server designed for serial-to-Ethernet connectivity in hazardous locations. One PortServer TS Haz MEI is connected to each RTU along the pipeline. RealPort®, Digi’s patented COM port redirector (included), is loaded on the server in the centralized control room. RealPort establishes a connection between the host and RTU by creating a local COM or TTY port on the host computer, allowing the existing SCADA application to work without modification.

Several key features helped solidify the utility’s decision to migrate to the PortServer TS Haz MEI:

  • Extended temperature range of -35° C to 74° C can withstand hazardous locations
  • Class 1, Division 2 certification meets hazardous location safety requirements
  • Screw terminal for power
  • RealPort COM port redirector offers seamless migration from current solution
  • Easy implementation of automatic redundant computer solutions for high availability
  • Data is transferred over a TCP/IP connection, eliminating expensive dedicated modem lines
  • Modbus serial to Modbus TCP conversion capability is supported for applications that can speak Modbus TCP directly

With PortServer TS Haz MEI and RealPort, the natural gas utility replaced its analog modems and eliminated recurring monthly costs associated with the old modems. It also gained an instant failover plan, since RealPort can be installed on multiple servers at no added cost.

Connecting to pipeline RTUs over TCP/IP

Now you can...
Implement serial-to-Ethernet connectivity to collect data from RTUs along a pipeline, without modifying the existing SCADA application

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