Introduction
This document is compiled for the purposes for guiding the user on how to SCAN ASCII based strings inside of a PLC into Adroit SCADA via the string Agent.
In this case the PLC being used is Melsec-iQ-F FX5 PLC, and the engineering software being used would be GX Works3.
The Method:
The PLC will contain a set of registers that will contain the string data. The string data in this case will be in the format of ASCII format.
Now, the ASCII data is being stored in word registers. Each register will contain 16bits of data. Each ASCII character requires a byte of data (8bits), and thus 2 characters can be extracted from each register (16bit).
These are then scanned into a String instance called a tag, in Adroit.
A list of consecutive registers can be scanned (up to 79) – to construct a string-based message.
An Example:
Suppose we require to display the first then Capital letters of the alphabet in a single string tag instance in Adroit, to be displayed.
We will need to store the data in the PLC.
In this case, say, we start at register D300:
Data can be displayed in Binary:
Data can be displayed in Hex format:
The following ASCII table indicates the complete ASCII table:
For this example – we will look that the following list: (for the simple demonstration test)
Since we require to display 10 ASCII Characters (a byte each), we will require 5 words. (16-bit each):
The following scanning will transpire:
On the Adroit Side – the scanning of the string agent tag instance will require a suffix for 10 characters, thus
S (For string) 10 (For 10 ascii characters)
The device register address suffix format for scanning can be displayed as follows:
In this case:
The scanned result will look like this:
As a result – within the agent server – we get the following result:
A breaking linking the word order and the string character order is being displayed as follows:
Video Demonstrations:
The following video demonstrates the principle based on the above concept:
(in this video the communication setup via the PLC configuration settings and the Adroit driver device setup is also demonstrated)
The following video demonstrates an application example:
Reference and Information Resources
Adroit SCADA sample program zipped
Melsec iQ-F FX5 GX Works3 sample program zipped
Simple Concept:
Concept demonstration:
