National Instruments FP-3000 Fault State and Mode Shedding

Appendix D Advanced Function BlockBehavior

FieldPoint FP-3000 User Manual D-4

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National Instruments Corporation

Bypassing Cascade Initialization

If cascade initialization is unnecessary, you can bypass it by leaving the

back calculation input of the upstream block unwired. By manually writing

a status of Good, Non-cascade to the back calculation input, the block

bypasses cascade initialization and immediately transitions to automatic

control. The upstream block signals to the downstream block that cascade

initialization has been bypassed by setting its output to a status of Good,

Non-cascade.

Fault State and Mode Shedding

To allow for safe control of a process, even in the event the input sensors or

control algorithms fail, FOUNDATION Fieldbus provides fault state and

mode shedding. Fault state is used when an output block is in Cascade

mode. Mode shedding is used in Remote or Remote Cascade modes.

Fault State

FOUNDATION Fieldbus output function blocks (AO, DO, and CDO)

support a faultstate to deal with the case where the control of the output

block has been lost while the block is in Cascade mode. If the block is in

Cascade mode, and CAS_IN has a bad quality for longer than the time

specified in the FSTATE_TIME parameter, the block enters faultstate. If the

Faultstate Use Value option is set in the IO_OPTS parameter, the

block uses the value in FSTATE_VAL as its output value. If the option is not

set, it holds the value it had at the time the input went bad until the cascade

can be reestablished.

Mode Shedding

For remote modes in which the cascade input is periodically written by a

host application, FOUNDATION Fieldbus provides mode shedding to

handle failure of the host application. For the RCas mode and ROut modes,

there are two timeout parameters in the resource block: SHED_RCAS and

SHED_ROUT. If the block is in a remote mode and the block input being used

(RCAS_IN or ROUT_IN) is not updated within the timeout period, the block

sheds to a higher priority mode. The action taken by the block when mode

shedding occurs is defined by the SHED_OPT parameter, as described in

TableD-1. The shed condition ends when the host writes the remote input

parameter. If a normal return shed option is selected, the block attempts to

enter the original remote mode. If a no return shed option is selected, the

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