Pepper Computer RS232, RS485 user manual ISaGRAF Operate Calls

Chapter 4 Digital Modules SMART I/O User’s Manual

4.1.9.2 The ISaGRAF Operate Calls

Operate calls are built into a program using ST or FBD languages when defining the project. A typical use could be at the initialization stage to check that the SMART-Modules are in fact located where they have been programmed to be. The syntax of the operate call is as follows:

Syntax

<return variable> := OPERATE(<source var>, COMMAND, <source data>);

Here the return variable is assigned a value associated with the selected COMMAND parameter. Each SMART-Module possesses its own set of these COMMANDS.

Example

<error.code>:= OPERATE(<channel>, O_INIT_CODE, 0);

O_INIT_CODE is one of a number of distinct commands recognized by the PEP Modular Computers’ implementation of board drivers and checks for example that the board is located where the program expects it to be.

channel provides channel specific information and in the example shown here, any of the 8 input channels may be used. The last parameter is not usually used by PEP implementations and is set to 0 (zero).

The error.code returns a value of zero if no error was detected, other- wise it returns a non-zero value depending on the error encountered. A list of these error codes may be found in the PEP online help.

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March 12, 1996 ©1996 PEP Modular Computers GmbH Page 4 - 17