The following program organization units (POU) are defined in IEC 61131-3:
ofunction
ofunction block
oprogram
odata structure
olist type
ounion
ointerface
EcoStruxure Machine Expert offers additional POUs for the creation and management of test cases:
otest case
otest series
otest resources
The designator is composed of a POU prefix and as short a name as possible (for example, FB_GetResult). Just like a variable, capitalize the first letter of each word in the basis name. Write the rest in lower case letters. Form a composite POU name from a verb and a noun.
The prefix is written with an underscore before the name and identifies the type of POU based on the table:
|
POU prefix |
Type |
Use |
Example |
|---|---|---|---|
|
SR_ |
PROGRAM |
program |
SR_FlowPackerMachine |
|
FB_ |
FUNCTION_BLOCK |
function blocks |
FB_VisuController |
|
FC_ |
FUNCTION |
functions |
FC_SetUserFault |
|
ST_ |
STRUCT |
data structure |
ST_StandardModuleInterface |
|
ET_ |
Enumeration |
list type |
ST_StandardModuleInterface |
|
UT_ |
UNION |
union |
UT_Values |
|
IF_ |
INTERFACE |
interface |
IF_CamProfile |
|
TC_ |
Testcase* |
test case |
TC_MultiCam |
|
TS_ |
TestSeries* |
test series |
TS_Robotic |
|
TR_ |
Test resources* |
test resources |
TR_Axes |
|
*IEC identifier enhancements introduced by Schneider Electric ETest plugin |
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