Moore Industries NET Concentrator System AOM, Руководство пользователя

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NET Concentrator System
®
NCS
- 29 -
Moore Industries-International, Inc. www.miinet.com
ISaGRAF Control Engine
The ISaGRAF Runtime Kernel is an embedded control
engine which runs inside a NCS Interface Module.
The control engine executes programs referred to
as “resources” which are created by the PC-based
ISaGRAF Workbench. The Workbench is an
IEC-61131 compliant programming environment used
to author, compile, and download applications to
one or more Interface Modules. Interface Modules
and their connected I/O modules are referred to
as “configurations” and can execute one or more
resources. Application scope can vary in scope. For
example:
1. A stand-alone station performing calculations
on data from input channels and driving
outputs.
2. A geographically distributed system where
remote peers exchange I/O and status data.
This section discusses aspects of ISaGRAF which are
specific to the NCS. Using the Workbench to create
applications is outside the scope of this manual.
Please refer to ISaGRAF Workbench User Manuals.
NCS ISaGRAF Execution
When the NCS Interface Module starts up, it starts
the ISaGRAF Configuration Manager. This service
performs two main tasks: Listen for and respond to
communication from the Workbench, and to load and
execute resources. Resources downloaded by the
Workbench are stored as a series of files in the hds
folder of the file system.
When a resource is started, it will be executed at
the programmed Cycle Time. During each cycle,
inputs are read, the program(s) executed, and then
outputs are written. If part of a distributed application,
data is also consumed from, and produced for other
peers. Program logic can make use of function blocks
embedded in the NCS. Blocks provide the ability to
read and write local MODBUS registers, to control the
data logger, and an implementation of a PID control
algorithm.
Programming mistakes (i.e., infinite loops) can make
the system appear frozen, and unresponsive to
attempts to download a new resource. The errant
resource will have to be removed from the system. If
the Safe Mode Jumper is installed the Configuration
Manager will not be started. This allows the offending
resource to be deleted via FTP.
Target Definition File
The Workbench must be given information about
the NCS in order to be able to properly compile the
programs. This information is contained in the Target
(or PLC) Definition File, and is “imported” into the
workbench at the start of a project. The best way
to obtain this file is to retrieve it by navigating to the
following web page (where <IP> is replaced by the IP
address of the NCS):
http://<IP>/api/mt
Click “Save As…” and save this page as a file
with no extension. Follow ISaGRAF Workbench
Documentation to import this file. Once imported,
each configuration’s “Target” setting needs to be
changed to CPMS regardless of which Interface
Module you have.
I/O Module Wiring
Process data is accessed by using the I/O Wiring
feature of the Workbench. Here, you specify which
I/O modules are present, and “wire” variables to each
channel’s PV or status value. When selecting the I/O
modules, keep the following in mind:
- Use only devices which match the module type,
i.e. use “Tim(**)” but not “Tim_PV_Data(**)”.
- The Module Parameter is a one based number
(ie the first module is module 1.)
When a resource is started, it checks that the modules
it expects match those which are actually present. An
error bit is set if there is a mismatch.