FieldBus, the wave of the future FieldbusELC-213Fieldbus Presentation by Clifford T. Johnson, PE, Control Systems Engineer But I do not recommend it for every system. It should not be used for systems with less than 100 control loops The primary reason that the field bus was develop was to save construction cost of wiring individual field devices back to I/O Cabinets that were used in the early Days of the DCS and PLC. However, it turned out that the construction costs were offset by the increase in engineering PC-ControLAB

TodayAssignment & LabELC-213 Assignment & Lab FieldBus, the wave of the future PC-ControLab: Tuning demo

BusELC-213 AS-i (Actuator Sensor Interface) ASi AS-i is the easiest network to install

IS Easiest to installELC-213 AS-i is simply 2 wires AS-i primarily operates On-Off ball valves that incorporate a rotary valve monitor that is addressed using 5 position dip switch ASi

HighlightsELC-213 AS-i Network Highlights Technology Developer AS-i Consortium Introduced 1993 Openness Multiple vendors, 800+ products, 150 Vendors Type of Network Sensor Bus Physical Media 2-wire cable (flat or round) Network Topology Bus, Ring, Tree, Star Maximum Devices - v nodes (or 248 I/O points) - v nodes (or 434 I/O points) - Maximum Distance 100 meters - Maximum Distance with repeaters 300 meters (max. of 2 repeaters can be used) ASi AS-i is the easiest network to install

6 Fieldbus provides two-way, multi-drop digital communication between devices on the plant floor as well as the automation and display systems. Thus, FFB is essentially a Local Area Network (LAN) for field devices. Fieldbus Automation and Display Systems P L F Process Plant Foundation Fieldbus Technology (FFB) FoundationFieldbus-USAELC-213

Hardest to installELC-213 FFB Plant Network Hierarchy Foundation Plant Network Office Automation Mainframes Management Local Area Network Automation & Display Systems DCS’s, PLC’s, PC’s SCADA, Supervisory Systems Fieldbus Network Instrumentation & Control Transmitters, Controllers Valves & Actuators FFB is the only Fieldbus that provides power to the devices and that makes it very difficult to design & Install

Best overall ELC-213 ProFiBus Process Field Bus ProFiBus SIEMENS ET200C SIEMENS ET200C Bus R Star Ring Line FO RS 485 IEC

DeviceNETELC-213 DeviceNET By Allen-Bradley

DeviceNETELC-213 Allen-Bradley Developed DeviceNET For motor controls

What is Ethernet? The IEEE recognizes Ethernet as standard IEEE802.3 Defines layers 1 & 2 Layer 1 defines cables, connectors & electrical characteristics Layer 2 defines frame format, error checking, and physical addressing (MAC – Medium Access Control) The technology that Ethernet uses to determine when nodes can transmit is Carrier Sense, Multiple Access, with Collision Detection or CSMA/CD Application Presentation Session Transport Network Data Link Physical Ethernet ELC-213Not for process control

How does CSMA/CD work? Carrier Sense, Multiple Access, with Collision Detection (CSMA/CD) is a contention based access method: –Carrier Sense: listen before sending –Multiple Access: any device can send data if it doesn’t detect a “busy” signal. CSMA is analogous to many speaker phones where only one person can talk at a time Collision Detection senses when two nodes attempt to transmit simultaneously When a collision is detected, both nodes stop and wait a different, specified, period of time before retrying This is the underlying reason that Ethernet is termed non-deterministic Transmission speed (msec) _X_X Average and Standard Deviation determined by network loading Std. Dev. Ethernet ELC-213 Non Deterministic

Ethernet – Myth vs. Reality? Myth: Non-determinism: Any Ethernet network loaded above 40% will experience an exponential growth in transmission delay times and become non-operational. Reality: Ethernet delays are linear and can be consistently maintained under 2 ms for a lightly loaded network and 30 ms for a heavily loaded network. These delays are inconsequential for most process control applications and can be minimized by using switches and routers to manage network topology. However, Critical Control & Safety Systems do not use Ethernet because it is Non-deterministic Ethernet ELC-213Not for safety systems

FieldBUS TypesELC-213 Fieldbus Types Summary Sensorbus Seriplex ASI INTERBUS Loop Devicebus Device Net SDS Profibus DP LONWorks INTERBUS-S Fieldbus IEC/ISA SP50 Fieldbus Foundation Profibus PA HART Type of Devices Type of Control Process Control Logic Control Low-end bit Midrange byte High-end block Simple DevicesComplex Devices Easies t Hardest Best Overall

PC_ControLABELC-213 PC-ControLAB Demo PC-ControLAB is a active demonstration of a control Station that allows you to "TUNE" a simulated controller and view the results. you will download from resources the instructions for tuning a flow, Temperature and Pressure loop for optimum controls, then enter the tuning parameters on an to me as FLOW: Gain= XX; Reset= XX; (derivative is not used) then the same for PRESS & TEMP

PC_ControLABELC-213 PC-ControLAB Demo User-friendly interface resembles a control station. Auto/Manual mode selection buttons and indication Set point and output entry via "jog" buttons or move Pointer Tuning permits entry of Proportional Band in % and Reset in repeats/min. Load control buttons permit forcing a step change or enabling automatic load changes. You should simulate a load change by simply changing the set point

PC_ControLABELC-213 PC-ControLAB Demo Control menu permits selection of control strategies: Feedback Override (Selector) Dual Feedback Two forms of Feedforward Ratio Two forms of Decoupling Cascade Four forms of Model-Based Control

PC_ControLABELC-213 PC-ControLAB Demo

AssignmentELC-213 Homework ASSIGNMENT Web Link Find a site of a Pressure Transmitter that works on Foundation Fieldbus. web page LINK only to me by Sunday Ex: Johnson-Fieldbus PT- Ex: Johnson-Fieldbus PT- AD Lab: Johnson-PC_ControLab- Lab: Johnson-PC_ControLab-AD All s Subjects and File names must have You will lose 1-3 points for incorrect subject Subjects Subject : Subject :Your last Name-Subject-Assignment Date (AD)

InstrumentationELC-213 The End AlmostDone