National Instruments FP-3000 D

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National Instruments Corporation D-1 FieldPoint FP-3000 User Manual

D

Advanced Function

Block Behavior

This appendix explains advanced features of function blocks that are

unnecessary to establish simple control strategies. Use this information to

diagnose problems in control strategies and to develop systems that

implement supervisory control by a host computer.

Cascade Initialization

FOUNDATION Fieldbus provides a protocol called Cascade Initialization

that allows a control function block to smoothly transition from Man to

Auto mode. Cascade Initialization allows the PID algorithm to know the

current setpoint of the AO block to balance the actual setpoint with the

control’s setpoint over time. Cascade Initialization is also used to prevent

windup in the PID.

Parameter Connections for Cascade Initialization

Cascade initialization takes place between two blocks: an upstream

controlling block, and a downstream controlled block. In a PID loop, the

upstream block is the PID block, and the downstream block is the AO

block. In the case of cascaded PID blocks, the upstream PID feeds a

setpoint into a second PID that is acting as the downstream block. In both

cases, the parameter connections are the same. The output (OUT) parameter

of the upstream block is connected to the cascade input (CAS_IN)

parameter of the downstream block. This connection controls the setpoint

of the downstream block. To allow the upstream block to determine the

current setpoint of the downstream block, you must also connect the

backward calculation output (BKCAL_OUT) parameter of the downstream

block with the backward calculation input (BKCAL_IN) of the upstream

block. The connections are shown in FigureD-1.

Contents

Main Page Important Information Warranty Copyright Trademarks WARNING REGARDING MEDICAL AND CLINICAL USE OF NATIONAL INSTRUMENTS PRODUCTS Contents About This Manual Chapter 1 FP-3000 Network Module Overview Chapter 2 Installation and Configuration Chapter 3 Example Applications Chapter 4 Block Reference Appendix A Configuring the FP-3000 Appendix B Troubleshooting Appendix C Fieldbus Parameters Page Page Page Tables Page About This Manual Conventions Related Documentation FP-3000 Network Module Overview Overview of the FP-3000 Network Module Page Features of the FP-3000 Network Module Function Blocks PID Control Block Instantiation Interoperability Link Active Scheduler (LAS) Functionality HotPnP (Hot Plug and Play) Field Upgradability Installation and Configuration Install the Device Description File Page Updating the Device Description Mount the FP-3000 and Terminal Bases Mounting the FP-3000 on a DIN Rail Connecting Terminal Bases with DIN Rail Mounting Removing the FP-3000 from the DIN Rail Mounting the FP-3000 to a Panel Connecting Terminal Bases with Panel Mounting Removing the FP-3000 and Terminal Bases from the Panel Mount I/O Modules onto Terminal Bases Connect Power to the FP-3000 Calculating Power for a FieldPoint Bank Power-On Self Test (POST) Connect the FP-3000 to the Fieldbus Network Page LED Indicators Page HotPnP (Hot Plug and Play) HotPnP During Operation Inserting New I/O Modules Replacing I/O Modules Updating the FP-3000 Firmware Page Page Page Example Applications Initial Power On: Assigning Address and Device Tag Example 1: Converting a 420 mA Pressure Sensor to Fieldbus Using FP-3000 Getting Started Convert the Pressure Sensor Reading Create Function Block Page Set the Input Range Scale the Reading Page Example 2: Temperature Control with the FP-3000 Getting Started Taking Temperature Readings Create an FP-TC-120 Block Set the Input Range and Thermocouple Type Scale the Reading Page Controlling a Heating Element Instantiate an FP-AO-200 Block Set the Output Range Scale the Output Page PID Control Instantiate a PID Block Scale the PID Connect the PID to the AI and AO Blocks Download and Bring the Loop into Auto Tune the PID Alarming Page Page Block Reference Block Overview Function Blocks Resource Block Types of Function Blocks AI (Analog Input) AO (Analog Output) PID (ProportionalIntegralDerivative) DI (Discrete Input) DO (Discrete Output) CDO (Complex Discrete Output) LOG (FieldPoint Log Block) (FP-3000 Specific) Function Blocks and FieldPoint Modules PID Control Alarming Alarm Parameters UNACKNOWLEDGED ALARM_STATE/UPDATE_STATE TIME_STAMP SUBCODE VALUE Status and Mode Handling Overview Status Handling Quality Substatus Limit MODE_BLK Parameter and Mode Handling Target Mode Actual Mode Permitted Mode Normal Mode FP-3000 Specific Parameters CFG_OPTS DEV_OPTS EXECUTION_STATISTICS FIELDPOINT_CHANNEL FIELDPOINT_MODULE FP_AI_100_RANGE FP_AI_110_RANGE FP_AI_111_RANGE FP_AO_200_RANGE FP_CJC_SOURCE FP_MOD_STATUS FP_NOISE_REJECTION Page VERSION_INFORMATION A Configuring the FP-3000 Simulate Enable Page B Troubleshooting Fieldbus Communication Problems Setting Device Tag and Network Address Page I/O Module Problems Software Configuration Problems Page Page Page C Fieldbus Parameters ACK_OPTION ALARM_HYS ALARM_SUM ALERT_KEY BINARY_OP BKCAL_HYS BKCAL_IN BKCAL_OUT BLOCK_ALM Page BLOCK_RESET BYPASS CHANNEL CHECKBACK CLR_ FSTATE CONFIRM_TIME CONTROL_OPTS CYCLE_SEL/CYCLE_TYPE DD_RESOURCE Page FEATURE_SEL/FEATURES FF_GAIN FF_SCALE Page Page L_TYPE LIM_NOTIFY LO_ALM LO_LIM LO_LO_ALM LO_LO_LIM Page NV_CYCLE_T OP_CMD_CXO OUT OUT_HI_LIM OUT_LO_LIM OUT_SCALE PV PV_FTIME PV_SCALE RATE RCAS_IN RCAS_OUT RESET RESTART ROUT_IN ROUT_OUT RS_STATE SAFEGUARD_CL SAFEGUARD_OP SET_FSTATE SHED_OPT SHED_RCAS SHED_ROUT SIMULATE SP_HI_LIM SP_LO_LIM SP_RATE_DN SP_RATE_UP ST_REV STATUS_OPTS STRATEGY TAG_DESC TEST_RW TRK_IN_D TRK_SCALE UPDATE_EVT WRITE_ALM WRITE_LOCK WRITE_PRI XD_SCALE Advanced Function Block Behavior Cascade Initialization Parameter Connections for Cascade Initialization Mode and Status Behavior during Cascade Initialization Remote Cascades Bypassing Cascade Initialization Fault State and Mode Shedding Fault State Mode Shedding Page E Specifications Network Environment Compliance F Technical Support Resources Web Site FTP Site Fax-on-Demand Support E-Mail Support Telephone and Fax Support Glossary Index Numbers A B C D E F Page Page G H I L M N O P Q R S T U V W X