The property prefix identifies the properties of variables and constants.
|
Prefix Type |
Use |
Syntax |
Example |
|---|---|---|---|
|
c_ |
VAR CONSTANT |
local constant |
c_xName |
|
r_ |
VAR RETAIN |
remanent variable type retain |
r_xName |
|
p_ |
VAR PERSISTENT |
remanent variable type persistent |
p_xName |
|
rp_ |
VAR PERSISTENT |
remanent variable of type retain persistent |
rp_xName |
|
i_ |
VAR_INPUT |
input parameter of a POU |
i_xName |
|
q_ |
VAR_OUTPUT |
output parameter of a POU |
q_xName |
|
iq_ |
VAR_IN_OUT |
in-/output parameter of a POU |
iq_xName |
|
ati_ |
AT %IX x.y AT %IB z AT %IW k |
input variable that should write on the IEC input area |
ati_x0_0MasterEncoderInitOK |
|
atq_ |
AT %QX x.y AT %QB z AT %QW k |
output variable that should write on the IEC input area |
atq_w18AxisNotDone |
|
atm_ |
AT %MX x.y AT %MB z AT %MW k |
marker variable that should write on the IEC marker area |
atm_w19ModuleNotReady |
NOTE:
oDo not declare constants as RETAIN or PERSISTENT.
oDo not declare any RETAIN variables within POUs. This administers the complete POU in the retain memory area.
Example of AT-Declared Variables
The name of the AT-declared variable also contains the type of the target variable. It is used like the type prefix.
ati_xEncoderInit AT %IX0.0 : BOOL;
atq_wAxisNotDone AT %QW18 : WORD;
atm_wModuleNotReady AT %MW19 : WORD;
NOTE: A variable can also be allocated to an address in the mapping dialog of a device in the controller configuration (device editor). Whether a device offers this dialog is described in its documentation.
