Operation Benefits Freedom to Choose. Power to Integrate. 1 1 - PowerPoint PPT Presentation

Operation Benefits Freedom to Choose. Power to Integrate. 1 1 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Operation Benefits Topics � Higher performance control � Early process warning from device alerts � Increased availability 2 2 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

High Performance Digital Closed Loop Control Freedom to Choose. Power to Integrate. 3 3 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Some “Digital Control Systems” Aren’t Hardwired Fieldbus Real-time process Analog Digital control (4-20 mA) Device Digital Digital management (HART and proprietary) � If it’s not fieldbus, it’s not digital control system 4 4 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

End-to-End, Fieldbus Control is Faster � Analog Control � Fieldbus Control – AI scan, controller, and – AI scan, controller, and AO scan asynchronous AO scan asynchronous 250 ms 250 ms 250 ms Controller Controller AI AO AO AI PID AO > 2 x Controller Cycle 5 5 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Scheduled Execution and Punctual Communication � FF communication and execution is synchronized – Shortest possible dead-time Designed for process control – Precisely periodic sampling: no jitter Controller PID PID PID PID PID PID PID Transmitter AI AI AI AI AI AI AI Valve AO AO AO AO AO AO � AI/AO and other buses are asynchronous – Longer dead-time – Sampling jitter Controller PID PID PID PID PID PID PID PID Transmitter AI AI AI AI AI AI AI AI AI Valve AO AO AO AO AO AO AO AO AO 6 6 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

What is the Significance of Control Response Period? � It all adds up to process variability – Multiple loops per processing units – Multiple processing units per plant � Translates into better quality and throughput � Leading process licensors specify 300 ms control loops 7 7 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Advanced: Time Division Multiplexing � FOUNDATION fieldbus � Other buses – Scheduling – "Free running" • Synchronized – Longer time • Precisely periodic – Jitter = sampling period not (isochronous) constant ⎛ ⎞ 1 dPV ∫ = × + − × ⎜ ⎟ OUT P e e dt D ⎝ ⎠ I dt e = PV-SP dt = sampling period must be constant Designed for process control 8 8 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Easy: Scheduling is Automatic Schedule is automatically created 9 9 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Fast Below 300 ms Loops Now Possible � Fast devices AI TX2 – Fast blocks Link • < 30 ms CV2 PID AO – Fast links AI TX1 Link • << 30 ms CV1 PID AO � Control in the Field – Extensive block library Unscheduled • ARTH, ISEL, CS... 60 ms (< 30%) 250 ms Current Generation First Generation Pressure Positioner Pressure Positioner AI 20 ms 100 ms PID 30 ms 120 ms AO 25 ms 95 ms Link 30 ms 30 ms 10 10 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

ISC Study on Control in the Field � “Control in the field: analysis of performance benefits” study from ISC (industrial systems and control) 11 11 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Easy Operation - PID Auto Tuning for CIF � On-demand or adaptive tuning of PID � Recommends tuning based on test � Loop remains under control during test Control-in-the-field does not mean just “simple” PID 12 12 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Early Warning Act before process is affected Freedom to Choose. Power to Integrate. 13 13 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Integrated Control System � Engineering station � Maintenance station – System configuration – Device management – FF device commissioning – Process visibility – Device configuration � Operator station – Process operation – Process alarms – Critical device failure diagnostics Traditional Plus: Plus: Plus: Architecture Device Configuration Device Diagnostics Process visibility Engineering Operator Operator Operator Maintenance 14 14 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Smart Diagnostics - Integrated Device Diagnostics � Normal operation... � Device failure... � Faceplate... � Diagnostics – No device configuration by operator Detailed diagnostics in two clicks Help on the third 15 15 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

On/Off Valves � Fieldbus does discrete too � One pair of wires for multiple on/off valves � One pair of wires for solenoid and limit switches � Diagnostics � HART not applicable 16 16 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Status If its not the process, don’t trip Freedom to Choose. Power to unnecessarily Integrate. 17 17 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Digital All the Way - Digital Closed Loop Control Initiate Fault-State Command Validity: Good/Bad/Un Limited: High/Low Designed for certain Bumpless Transfer process control Windup Protection Fault-state Status Speed Status Propagation (CIF & CIC) � 25 times faster than � Validated information – Quality and limits hybrids of analog/digital � Windup protection � 250 ms loops possible � Bumpless transfer for valves � Real-time value and � Fault-state for valves status Only fieldbus eliminates the analog � etc. signal 18 18 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Process Variable Validity � Hardwired � Fieldbus – Device drives current – Device health indicated <4 mA or >20 mA on by associated status device failure – Controller holds last • Looks like process position on device problem failure – PID counteracts thus • Shutdown is optional tripping the loop – Operator can easily – Operator cannot tell distinguish process the difference between problem from a device a process alarm and a problem device alarm 19 19 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Valve and Positioner � Actual position transmitter feedback transmission on the same two wires – Further reduced wiring Continuous, real- – No AI card time, actual – More than just value: status position feedback � Software limit switches for every control valve – No DI cards – No extra wiring � Easy to add feedback as an afterthought � Bumpless transfer on local hand operation – Smoother operation � Bumpless firmware download – Upgrade while process is running, without replacing circuit board 20 20 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Easy Operation - Status in Historian � Status logged and shown next to value and color codes trend 21 21 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Fidelity Freedom to Choose. Power to Integrate. 22 22 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Digital Fidelity - Better Accuracy � Accurate measurements are not distorted by signal conversations: – Digital to analog – Analog to digital � Particularly important in some flow and level applications where small amounts correspond to a lot of money Digital AI BUS CTRL A/D FF CPU Transmitter 4-20 mA CPU D/A FF Digital Digital 23 23 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Easier and Safer: High Signal Integrity � Digital signal does not get "limited" Any distortion of a digital – If 20 mA becomes 18 mA you won't know process • Increase in resistance due to terminal corrosion variable is alerted – If 16 mA becomes 18 mA you won't know • Ground loop due to inadvertent ground leakage � Digital signal distortion does not go undetected – It is not possible to detect distortions in an analog signal Resistance = Voltage Drop = Limited Current Marshalling Analog PV 4-20 mA is AI distorted Leakage = Ground Loop = More Current Field Junction Box 24 24 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.

Easier and Safer - Real Number Engineering Unit Upper Limit � Measure to full sensor limits 20 mA / 10 ft 13 ft – Reading not saturated at 100% 20 mA /10 ft – Better understanding during abnormal 20 mA 10 ft conditions Normal Range 4 mA Digital Range AI BUS CTRL Range Lower A/D FF CPU Transmitter Limit 4-20 mA CPU D/A FF Digital Digital 25 25 Freedom to Choose. Power to Integrate. Freedom to Choose. Power to Integrate.