Ausenco was selected by contractor GAS Arabian Services Co., Ltd. to provide a PLC-based data acquisition system in conjunction with an EFA Technologies LeakNet leak detection system for Saudi Aramco’s SHBAB pipeline.
The SHBAB pipeline system includes one 46-inch diameter pipeline and one 30-inch diameter pipeline, with a combined total distance of approximately 200 km.
Ausenco provided the front-end communications system, which collects and transmits data from 25 remote terminal units (RTU) on the pipeline to the EFA LeakNet™ system. (The RTUs were provided by GAS).
The system includes an interface for receiving data over Modbus communications from analog to Modbus converters, and then scaling to analog engineering unit values and setting quality flags for the LeakNet™ application.
The panel includes a Rockwell Automation Control Logix PLC, which is configured for Ethernet communications to the LeakNet™ computer.
Ausenco programmed three devices for this application:
- Rockwell ControlLogix processor (Logix5000 software)
- Prosoft MVI56-MNETC (Prosoft Configuration Builder software)
- Moxa M3480 Modbus Gateway (MGate Manager software).
The Prosoft module was configured with the Modbus read commands, and programmed using the Configuration Builder Software.
The PLC and Prosoft identify each field device as a number, which corresponds to the Siemens OTN assigned serial port.
The Moxa gateway uses virtual ports to assign the PLC\\Prosoft number to the actual Modbus slave number.