ST Examples

Every channel in IO Mapping is already exposed as a global variable through its DefaultMapping name — IN0–IN6, OUT0–OUT5, AN0–AN2, LED and TEMPERATURE are usable directly in any POU without declaring or mapping them.

Blink the onboard LED

PROGRAM PLC_PRG
VAR
    blinker : TON;
END_VAR

blinker(IN := NOT blinker.Q, PT := T#500ms);
IF blinker.Q THEN
    LED := NOT LED;
END_IF

Digital pass-through

Mirror each digital input onto the corresponding output:

PROGRAM PLC_PRG
OUT0 := IN0;
OUT1 := IN1;
OUT2 := IN2;
OUT3 := IN3;
OUT4 := IN4;
OUT5 := IN5;

Analog threshold

AN0–AN2 are raw 12-bit ADC counts, 0…4095 over 0…3.3 V. Half scale is 2048:

PROGRAM PLC_PRG
OUT0 := AN0 > 2048;          // above ~1.65 V

Converting to volts:

PROGRAM PLC_PRG
VAR
    rVolt : REAL;
END_VAR

rVolt := WORD_TO_REAL(AN0) * 3.3 / 4095.0;

Dimming an output

Any output can be switched to PWM at runtime — see IO Mapping › PWM outputs.

PROGRAM PLC_PRG
VAR
    ramp : UINT;
END_VAR

PWM_ENABLE := 2#0000_0100;          // OUT2 (GP8) becomes a PWM output

ramp := ramp + 256;                 // wraps on its own at 65535
PWM2 := ramp;                       // slow fade

To go back to on/off, clear the bit: PWM_ENABLE := 0; and OUT2 commands the pin again.

The carrier frequency is not set from ST: it is a device parameter (9200 for OUT0/OUT1, 9201 for OUT2/OUT3 and the LED, 9202 for OUT4/OUT5), applied when the application starts. The duty stays 0…65535 whatever frequency you pick.

Temperature alarm

PROGRAM PLC_PRG
OUT5 := TEMPERATURE > 70.0;   // drive an alarm output past 70 °C

TEMPERATURE is the die temperature of the RP2350A, not the ambient temperature.

Serial communication

See Serial Ports for a complete open/write/read example over COM2 and COM3.