Black Box IC108A Guia do Utilizador descarregar pdf (Página 11)

Advant

Smart Device (HART

) Interface User’s Guide

Section 1.8 Product Overview

3BUR 001 085R0001 REV A 1-7

The data base used by the interface is downloaded when the interface is powered-up or reset.

After a Smart Device Interface configuration is downloaded, data tables (CCF channel tables)

are allocated for analog and digital input values read from the smart devices. Channel

assignments relate to a particular smart device 16-bit word (register) or 1-bit (coil) instead of

hardware connections.

Periodic scanning of the smart device data by the SHIM commences at a rate of three times per

second. During a scan, commands requesting data are sent to each smart device. More than one

command may be required in order to read all required data. Information concerning what and

how much data is read is obtained from Smart Device Interface configuration tables. If a hand-

held monitor is placed on-line with a smart device, the rate at which the SHIM scans smart

device data drops to one time per second.

The smart devices respond to each command by sending back the requested data. The smart

device configuration then specifies how the smart device data is stored in the CCF control loop.

Figure 1-1 shows an example of the smart device/CCF communication scheme. CCF accesses

values read from smart devices based on the input channel specified for each loop.

When a smart device fails to respond to two consecutive commands, a message is generated

informing the operator of a smart device communications failure and the data qualities of loops

associated with the smart device are set to BAD. The software continues to attempt to

communicate with the smart device without generating further messages.

No communication is initiated by a smart device. Only responses to Advant OCS initiated

commands are accepted.

Transfer of smart device variables to the Advant OCS data base via CCF loops that receive the

variables can provide the following functions within the Advant OCS:

• Processing of smart device variables by the CCF loops that receive them, or by other CCF

loops.

• Trending of smart device variables.

• Interaction with TCL programs.

• Inclusion of smart device variables in reports produced by the Report Services software.

• Inclusion of smart device variables in displays produced by the Display Builder software.

• Storing of smart device variables by the Historical Services software.

• Generation and logging of alarms for smart device variables.

Figure 1-1. Smart Device/CCF Loop Communication Scheme

CCF Data Base

CCF Continuous Loop

Analog

Input

Other

FCMs

Smart Device Interface

1 2 ... 6 7 8 9 10 11 12 13 14 15 16 ... 117 118

Comentários a estes Manuais

Sem comentários

Black Box IC108A Guia do Utilizador Página 11

Comentários a estes Manuais