Upgrade from V4.2.0-4.3.0 to V4.40-V4.50 : change Float variables word order



Goals and Symptoms

Upgrading an application from V4.2.0-4.3.0 to V4.4.0-4.5.0, there could be an issue with the word order of the Float variables.
Below is the explanation, and the solution

Facts and Changes

word order float floating variables high first low double

Causes and Fixes

The "Double Word word order" setting (at the EQUIPMENT level in I/O Manager in the editor) was introduced in Vijeo-Designer 4.2.0. It only concerned the 32-bit Integer variables. The default setting was "High word first" but the user had and has the option to change it to "Low word first". Float variables, which are 32-bit variables as well, were not affected by this setting. They actually didn't have any setting. Their word order was by default "Low word first" (but it didn't appear in the editor), with no possibility for the user to change it.

In Vijeo-Designer 4.3.0, the situation was exactly the same as in Vijeo-Designer 4.2.0.

In Vijeo-Designer 4.4.0, the change was to make this "Double Word word order" setting affect both 32-bit Integer variables and Float variables. This change had two reasons:
1. Allow users to change the word order for Float variables. In Vijeo-Designer 4.3.0 and earlier versions, the word order for Float variables was fixed and users couldn't change it.
2. Make it easier on users to have only one Double Word word order setting for both types of variables: 32-bit Integer variables and Float variables.

In Vijeo-Designer 4.5.0, the situation is the same as in Vijeo-Designer 4.4.0, with one exception: 16-bit Float variables are now allowed (%MW address instead of %MF). These variables are not affected by the "Double Word word order" setting because they are "single word" variables.

The default value of the "Double Word word order" setting is "High word first". Therefore, for customers upgrading from Vijeo-Designer 4.2.0 or 4.3.0 (where their Float variables follow the "Low word first" default setting) to Vijeo-Designer 4.4.0 to 4.5.0 (where their 32-bit Float variables follow the "Double Word word order" setting), if they use Float variables in their applications, they have to change the setting from "High word first" (its default value in the editor) to "Low word first".

Legacy KB System (APS) Data: RESL181415 V1.0, Originally authored by FaMe on 01/03/2007, Last Edited by FaMe on 01/03/2007
Related ranges: Vijeo Designer