(IJACSA) International Journal of Advanced Computer Science and Applications, Vol. 3, No. 8, 2012 157 | Page www.ijacsa.thesai.org Review of Remote Terminal Unit (RTU) and Gateways for Digital Oilfield delpoyments Francis Enejo Idachaba Department of Electrical and Information Engineering Covenant University Ota. Ogun state Nigeria Ayobami Ogunrinde SPDC Nigeria Abstract— The increasing decline in easy oil has led to an increasing need for the optimization of oil and gas processes. Digital oilfields utilize remote operations to achieve these optimization goals and the remote telemetry unit and gateways are very critical in the realization of this objective. This paper presents a review of the RTUs and gateways utilized in digital oilfield architectures. It presents a review of the architecture, their functionality and selection criteria. It also provides a comparison of the specifications of some popular RTUs. Keywords—Digital Oilfield; Gateway; HMI; i-fields; RTU; Smartfields. I. INTRODUCTION The advent of Digital Oilfields, Smartfields or i-fields has led to an increase in the need to monitor, control and automate various systems at remote oil and gas production sites to increase production, reduce overall production cost, and reduce employee exposure. Control systems such as SCADA (Supervisory Control and Data Acquisition), or DCS (Distributed Control System) using Remote Telemetry Units and Gateways are deployed to achieve these control functions. The RTUs and gateways comprises of various components such as  HMI (Human Machine Interface)  RTU (Remote Terminal Unit): This collects the site data and sends it to a station via a communications system.  Supervisory systems/ Master station: this collects the information from the process and control the process. This is usually a computer.  Communication system that provides a means by which all components communicate securely without loss of data and information. Digital oilfield installations require bidirectional transmission of data from the sensors located in the field and control signals from the control room or the office domain to these sensors and devices located in the field. The data from the sensors are transmitted at defined intervals or by exception while the control algorithms used for the field devices can either be the on/off control or a variable control. This paper Ease of Use II. RTU Remote Terminal Unit (RTU) is a microprocessor-based device connected to sensors, transmitters or process equipment for the purpose of remote telemetry and control. RTUs find applications in oil and gas remote instrumentation monitoring, networks of remote pump stations, Environmental monitoring systems, Air traffic equipment etc. [1] RTUs with the aid of appropriate sensors, monitors production processes at remote site and transmits all data to a central station where it is collated and monitored. An RTU can be interfaced using serial ports (RS232, RS482, and RS422) or Ethernet to communicate with the central stations. They also support various protocol standards such as Modbus, IEC 60870, DNP3 making it possible to interface with 3rd party software. III. RTU ARCHITECTURE The RTU architecture comprises of a CPU, volatile memory and nonvolatile memory for processing and storing programs and data. It communicates with other devices via either serial ports or an onboard modem with I/O interfaces. It has a power supply with a backup battery, surge protection against spikes, real-time clock and a watchdog timer to ensure that it restarts when operating in the sleep mode.[2] Figure 1 shows the block diagram of a typical RTU configuration. A typical RTU hardware module includes a control processor and associated memory, analog inputs, analog outputs, counter inputs, digital inputs, digital outputs, communication interfaces and power supply [3] A. Central Processing Unit (Cpu) Current RTU designs utilize a 16bit or 32 bits microprocessor with a total memory capacity of 256kbytes expandable to 4 Mbytes. It also has two or three communication ports (RS232, RS422 and RS485) or Ethernet link. This system is controlled by a firmware and a real-time clock with full calendar is used for accurate time stamping of events. A watchdog timer provides a check that the RTU program is executing regularly. The RTU program regularly resets the watchdog timer and if this is not done within a