National Instruments FP-3000 Remote Cascades

Appendix D Advanced Function BlockBehavior

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National Instruments Corporation D-3 FieldPoint FP-3000 User Manual

To prevent windup, the control loop needs to be aware when it is unable to

control the process. If the downstream block can no longer control the

process, it reports a status of Bad to the upstream block. This breaks the

cascade until automatic control can be resumed, in which case cascade

initialization takes place again.

Remote Cascades

If a host application (rather than another block) provides the setpoint of a

block, FOUNDATION Fieldbus provides the Remote Cascade mode. The

remote cascade mode is equivalent to Cascade mode, except that the

cascade input parameter is RCAS_IN instead of CAS_IN, and the back

calculation output is RCAS_OUT instead of BKCAL_OUT. Unlike CAS_IN and

BKCAL_OUT, which are input/output parameters, RCAS_IN and RCAS_OUT

are contained parameters and can only be written by a host application. To

allow the controlled block to enter Remote Cascade mode, the host

application must act as the upstream block in the cascade initialization and

implement the status handling described above.

Figure D-2. Remote Cascade Model

There is a second remote mode in which a cascade must be initialized:

Remote Output (ROut mode). Unlike RCas mode, where the block setpoint

is set remotely, in ROut mode the block output is set by the host application.

The back calculation output for ROut mode is ROUT_OUT, and the cascade

input is ROUT_IN. Otherwise, cascade initialization proceeds normally.

RCAS_OUT

Downstream

RCAS_IN

Host

Application

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