ILOGICS 제품 사용설명서

# MPINO-8A8R

MPINO-8A8R is an all-in-one industrial Arduino with 8 digital inputs and 8 relay outputs. A single PCB integrates 4 analog inputs, 6 PWM outputs, 2 isolated high-speed counter inputs, 4 interrupt inputs, and RS-232·RS-485·UART·I²C communication.

Program the controller with Arduino IDE (Arduino C/C++) or MPINO STUDIO 2 (Arduino C/C++ & ladder logic).

See the [MPINO Series specifications](https://www.ilogics.net/docs/en-us_products:mpino_series#mpino_series_specifications “en-us_products:mpino_series”) for the board name, connection method, and first I/O numbers for MPINO-8A8R.


## Product Specifications

## Digital inputs

[See the one-channel digital-input check before wiring for the first time. →](https://www.ilogics.net/docs/en-us_guide:wiring#digital_input_one_channel_check “en-us_guide:wiring”)

The digital inputs are isolated by bidirectional optocouplers and accept DC 5~24V NPN or PNP signals. Select the input type through the COM0 wiring polarity.

### Example program · digital inputs

Use digitalRead() to display the D22~D29 input states every 200ms. HIGH is 1 and LOW is 0.

```cpp void setup() {

Serial.begin(115200);

}

void loop() {

for (uint8_t pin = 22; pin <= 29; pin++) {
  Serial.print(F("D"));
  Serial.print(pin);
  Serial.print(F(": "));
  Serial.println(digitalRead(pin));
}
delay(200);

} ```

Related built-in functions

#### Function example · consecutive-read filter: IdigitalRead()

Function prototype

```cpp bool IdigitalRead(uint8_t pin, uint8_t samples); ```

IdigitalRead(22, 5) reads D22 5 times consecutively. Update the state when all readings are HIGH or all are LOW; mixed readings retain the previous state. Unlike a time-based debounce filter, it inserts no delay between readings.

```cpp void setup() {

Serial.begin(115200);

}

void loop() {

const bool inputOn = IdigitalRead(22, 5);  // Read D22 five times consecutively and return the stable state
Serial.println(inputOn ? F("D22 ON") : F("D22 OFF"));
delay(200);

} ```

#### Function example · debouncing: Ibounce(), IbounceOn(), IbounceOff()

Function prototype

```cpp bool Ibounce(uint8_t pin, uint32_t debounceTime); bool IbounceOn(uint8_t pin, uint32_t debounceTime); bool IbounceOff(uint8_t pin, uint32_t debounceTime); ```

Compare three filters on the D22 input. Each returns the filtered ON/OFF state.

- `Ibounce(22, 30)`: Apply ON and OFF only after they remain stable for at least 30ms. - `IbounceOn(22, 500)`: Delay ON by 500ms; apply OFF immediately. - `IbounceOff(22, 500)`: Delay OFF by 500ms; apply ON immediately.

Each function operates independently, even on the same pin. Run the filters on every loop() iteration and display only the results at 200ms intervals.

```cpp unsigned long lastPrint = 0;

void setup() {

Serial.begin(115200);

}

void loop() {

const bool stable = Ibounce(22, 30);  // Filter D22 ON/OFF chatter over 30ms
const bool onDelayed = IbounceOn(22, 500);  // Delay only D22 ON by 500ms; apply OFF immediately
const bool offDelayed = IbounceOff(22, 500);  // Delay only D22 OFF by 500ms; apply ON immediately

if (millis() - lastPrint >= 200) {

  lastPrint = millis();
  Serial.print(F("Ibounce: "));
  Serial.print(stable);
  Serial.print(F(", IbounceOn: "));
  Serial.print(onDelayed);
  Serial.print(F(", IbounceOff: "));
  Serial.println(offDelayed);
}

} ```

#### Function example · input toggle: Ialt()

Function prototype

```cpp void Ialt(bool input, bool &state_var); ```

Ialt(input, state) inverts state whenever the input changes from OFF to ON. Pressing D22 once turns D62 ON; pressing again turns it OFF. Holding the input retains the state. The example debounces the input with Ibounce(22, 30) before passing it to Ialt(). outputOn is a global variable retained between calls, and Ialt() modifies it directly.

```cpp bool outputOn = false;

void setup() {

Serial.begin(115200);
digitalWrite(62, LOW);

}

void loop() {

const bool previous = outputOn;
const bool inputOn = Ibounce(22, 30);  // Filter D22 ON/OFF chatter over 30ms
Ialt(inputOn, outputOn);  // Invert outputOn on an OFF→ON input transition
digitalWrite(62, outputOn ? HIGH : LOW);

if (outputOn != previous) {

  Serial.println(outputOn ? F("D62 ON") : F("D62 OFF"));
}

} ```

## Relay outputs

[See the one-channel relay-output check before wiring for the first time. →](https://www.ilogics.net/docs/en-us_guide:wiring#relay_output_one_channel_check “en-us_guide:wiring”)

Relay outputs are dry contacts that physically connect each COM terminal to its output terminal. Connect a separate load power supply.

### Example program · relay outputs

Map inputs D22~D29 to outputs D62~D69 in order. When an input is HIGH, its corresponding output turns ON.

```cpp void setup() {

for (uint8_t pin = 62; pin <= 69; pin++) digitalWrite(pin, LOW);

}

void loop() {

for (uint8_t ch = 0; ch < 8; ch++) {
  digitalWrite(62 + ch, digitalRead(22 + ch));
}

} ```

## Analog Input

For A(0)~A(3), select each input range using the channel jumper position.

### Example program · analog inputs

Use analogRead() to display the ADC raw values (0~1023) of A0~A3. Each channel's voltage/current mode follows the actual product settings.

```cpp const uint8_t analogPins[] = {A0, A1, A2, A3};

void setup() {

Serial.begin(115200);

}

void loop() {

for (uint8_t ch = 0; ch < 4; ch++) {
  Serial.print(F("A"));
  Serial.print(ch);
  Serial.print(F(" ADC: "));
  Serial.println(analogRead(analogPins[ch]));
}
delay(500);

} ```

Related built-in functions

#### Function example · input range scaling: IanalogRead(), IanalogReadf()

Function prototype

```cpp int32_t IanalogRead(uint8_t ch, int32_t min, int32_t max); float IanalogReadf(uint8_t ch, float min, float max); ```

This example assumes A0 is configured for 0~5V input and A2 for 0(4)~20mA input. Both functions scale the ADC input to the specified min~max range. IanalogRead() returns an integer with the fractional part discarded; IanalogReadf() returns a floating-point value. This example displays the 0~5V input on A0 as both 0~100% and voltage. For the 0~20mA input on A2, specify a range of 0~20 to read the actual current.

```cpp void setup() {

Serial.begin(115200);

}

void loop() {

const int32_t percent = IanalogRead(A0, 0, 100);  // Scale A0 to an integer from 0~100%
const float voltage = IanalogReadf(A0, 0.0f, 5.0f);  // Scale A0 to a floating-point voltage from 0~5V
const float current = IanalogReadf(A2, 0.0f, 20.0f);  // Scale A2 to a floating-point current from 0~20mA
Serial.print(F("A0: "));
Serial.print(percent);
Serial.print(F(" %, "));
Serial.print(voltage, 2);
Serial.print(F(" V, A2: "));
Serial.print(current, 2);
Serial.println(F(" mA"));
delay(500);

} ```

#### Function example · 4~20mA range scaling: IanalogRead2(), IanalogRead2f()

Function prototype

```cpp int32_t IanalogRead2(uint8_t ch, int32_t min, int32_t max); float IanalogRead2f(uint8_t ch, float min, float max); ```

This example assumes A0 is configured for 0~5V input and A2 for 0(4)~20mA input. Scale a 4~20mA sensor input connected to A2 to a user-defined range. IanalogRead2(A2, 0, 100) returns an integer with 4mA mapped to 0% and 20mA to 100%. IanalogRead2f(A2, 4.0f, 20.0f) returns the current as a floating-point value. Below approximately 3.6mA, both functions return ANALOG\_READ2\_ERROR(65535); from approximately 3.6~4mA, they return the specified minimum.

```cpp void setup() {

Serial.begin(115200);

}

void loop() {

const int32_t percent = IanalogRead2(A2, 0, 100);  // Scale A2 4~20mA to an integer from 0~100%
const float current = IanalogRead2f(A2, 4.0f, 20.0f);  // Convert A2 4~20mA to a floating-point current
if (percent == ANALOG_READ2_ERROR ||
    current == (float)ANALOG_READ2_ERROR) {
  Serial.println(F("A2: 4-20mA input error"));
} else {
  Serial.print(F("A2: "));
  Serial.print(percent);
  Serial.print(F(" %, "));
  Serial.print(current, 2);
  Serial.println(F(" mA"));
}
delay(500);

} ```

#### Function example · moving average: analogReadAvg(), analogRead2Avg()

Function prototype

```cpp int32_t analogReadAvg(uint8_t ch, uint8_t samples); int32_t analogRead2Avg(uint8_t ch, uint8_t samples); ```

This example assumes A0 is configured for 0~5V input and A2 for 0(4)~20mA input. analogReadAvg(A0, 5) returns a moving average of the raw A0 ADC readings (0~1023). analogRead2Avg(A2, 5) averages the corrected A2 4~20mA values (4mA=0, 20mA=32767). Each function accumulates up to 5 valid readings from recent calls; it does not take 5 readings in one call. The maximum samples value is 20. analogRead2Avg() returns ANALOG\_READ2\_AVG\_ERROR(-1) for inputs below approximately 3.6mA.

```cpp void setup() {

Serial.begin(115200);

}

void loop() {

const int32_t voltageAvg = analogReadAvg(A0, 5);  // Moving average of up to 5 recent A0 ADC values
const int32_t currentAvg = analogRead2Avg(A2, 5);  // Moving average of up to 5 recent corrected A2 4~20mA values
Serial.print(F("A0 ADC average: "));
Serial.print(voltageAvg);
Serial.print(F(", A2 4-20mA average: "));
if (currentAvg == ANALOG_READ2_AVG_ERROR) {
  Serial.println(F("input error"));
} else {
  Serial.println(currentAvg);
}
delay(500);

} ```

### Example program · temperature sensor inputs

Run this only on products with A0 configured for NTC input. Use analogRead() to display the temperature-sensor ADC raw value (0~1023) of A0. Celsius conversion is explained in the built-in functions below.

```cpp void setup() {

Serial.begin(115200);

}

void loop() {

Serial.print(F("A0 ADC: "));
Serial.println(analogRead(A0));
delay(500);

} ```

Related built-in functions

#### Function example · read NTC temperature: ntcRead(), ntcReadf()

Function prototype

```cpp int ntcRead(uint8_t ch); float ntcReadf(uint8_t ch); ```

Run this only on products with channel A0 configured for NTC input. Read the temperature of the NTC 10kΩ (25℃), B=3950K sensor connected to NTC input A0. ntcRead() returns an integer equal to 10 times the Celsius temperature (25.3℃ → 253); ntcReadf() returns the Celsius temperature as a floating-point value (25.3). Both have a resolution of 0.1℃. Values outside the conversion range are clamped to -40℃ or 120℃, so do not use these values to detect an open or short circuit.

```cpp void setup() {

Serial.begin(115200);

}

void loop() {

const int temperature10 = ntcRead(A0);  // Return A0 temperature as an integer in Celsius ×10
const float temperature = ntcReadf(A0);  // Return A0 temperature as floating-point Celsius
Serial.print(F("ntcRead: "));
Serial.print(temperature10);
Serial.print(F(" (0.1 C), ntcReadf: "));
Serial.print(temperature, 1);
Serial.println(F(" C"));
delay(500);

} ```

## High-speed counter / Interrupts / Encoder

TCNT1 and TCNT5 are used as external clock inputs for TIMER1·TIMER5. I²C communication cannot be used simultaneously when SDA and SCL are used as encoder inputs.

### Example program · pulse counting

Count the TCNT1·TCNT5 isolated inputs as external timer clocks. Use rising edges on the MCU timer input; the value wraps to 0 after 65535. Read atomically and display every 500ms.

```cpp #include <util/atomic.h>

void setup() {

Serial.begin(115200);
TIMSK1 = 0;
TCCR1A = 0;
TCCR1B = 0x07;
TCNT1 = 0;
TIMSK5 = 0;
TCCR5A = 0;
TCCR5B = 0x07;
TCNT5 = 0;

}

void loop() {

uint16_t first, second;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
  first = TCNT1;
  second = TCNT5;
}
Serial.print(F("TCNT1: "));
Serial.print(first);
Serial.print(F(", TCNT5: "));
Serial.println(second);
delay(500);

} ```

Count FALLING edges on SDA(D20). The inputs have 4.7kΩ pull-ups (SDA/SCL). This software interrupt example reads the 32-bit value with ATOMIC\_BLOCK and displays it every 500ms. Lossless counting is not guaranteed at the maximum input frequency. Because this uses SDA·SCL, do not run it simultaneously with I²C communication.

```cpp static_assert(digitalPinToInterrupt(SDA) != NOT_AN_INTERRUPT, “Invalid interrupt input”);

#include <util/atomic.h>

volatile uint32_t pulseCount = 0;

void countPulse() {

pulseCount++;

}

void setup() {

Serial.begin(115200);
// SDA is pulled up; count when the external signal pulls it to GND
attachInterrupt(digitalPinToInterrupt(SDA), countPulse, FALLING);

}

void loop() {

uint32_t snapshot;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
  snapshot = pulseCount;
}
Serial.print(F("SDA pulses: "));
Serial.println(snapshot);
delay(500);

} ```

Related built-in functions

#### Function example · configure hardware pulse counter: TCNTSETUP()

Function prototype

```cpp void TCNTSETUP(uint8_t timerNumber, bool on32bit = false); ```

Use TCNTSETUP(timerNumber, false) to configure Timer1·Timer5 as 16-bit external-clock counters. Read the accumulated values from the TCNT1·TCNT5 registers. TCNTOUT() returns the overflow count in 32-bit mode, not the accumulated pulse count, so it is not used in this 16-bit example. Do not reconfigure Timer1·Timer5 with other timer functions.

```cpp #include <util/atomic.h>

void setup() {

Serial.begin(115200);
TCNTSETUP(1, false);  // Configure Timer1 as a 16-bit external pulse counter
TCNTSETUP(5, false);  // Configure Timer5 as a 16-bit external pulse counter

}

void loop() {

uint16_t first, second;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
  first = TCNT1;
  second = TCNT5;
}
Serial.print(F("TCNT1: "));
Serial.print(first);
Serial.print(F(", TCNT5: "));
Serial.println(second);
delay(500);

} ```

### Example program · encoder inputs

Connect phase A to SDA(D20) and phase B to SCL(D21). This x1 counting example uses a 4.7kΩ pull-up (SDA/SCL) and increments when phase B is LOW at a FALLING edge. The actual rotation direction depends on the phase A/B wiring. Because this uses SDA·SCL, do not run it simultaneously with I²C communication.

```cpp static_assert(digitalPinToInterrupt(SDA) != NOT_AN_INTERRUPT, “Invalid interrupt input”);

#include <util/atomic.h> #include <stdint.h>

volatile int32_t position = 0;

void readEncoder() {

// Increment if phase B is LOW at the phase A falling edge (x1 decoding)
if (digitalRead(SCL) == LOW) {
  if (position < INT32_MAX) position++;
} else {
  if (position > INT32_MIN) position--;
}

}

void setup() {

Serial.begin(115200);
// Encoder phase A → SDA(D20), phase B → SCL(D21)
attachInterrupt(digitalPinToInterrupt(SDA), readEncoder, FALLING);

}

void loop() {

int32_t snapshot;
ATOMIC_BLOCK(ATOMIC_RESTORESTATE) {
  snapshot = position;
}
Serial.print(F("Encoder: "));
Serial.println(snapshot);
delay(500);

} ```

## PWM Output

PWM outputs use an 8bit duty value by default, with an output voltage of DC 0~5V. PWM2 and PWM3 share interrupt-input functions.

### Example program · PWM outputs

Set analogWrite() duty value 128 in the 0~255 range on D5, D2, D3, D6, D7, D8 to output approximately 50% PWM.

```cpp void setup() {

analogWrite(5, 128);
analogWrite(2, 128);
analogWrite(3, 128);
analogWrite(6, 128);
analogWrite(7, 128);
analogWrite(8, 128);

}

void loop() { } ```

Related built-in functions

#### Function example · specify duty value: PWM()

Function prototype

```cpp void PWM(uint8_t pin, uint16_t val, bool onDutybit16 = false); ```

PWM(pin, val, onDutybit16) sets the duty value. The 8-bit range is 0~255; with the third argument true, the 16-bit range is 0~65535. Output the 16-bit midpoint value 32768 on D5. D5·D2·D3 share Timer3, and D6·D7·D8 share Timer4; use the same resolution on the same timer. Start after calling PWM\_RESET().

```cpp void setup() {

PWM_RESET();  // Stop PWM timers and reset their modes
PWM(5, 32768, true);  // Output a midrange 16-bit duty value on D5

}

void loop() { } ```

#### Function example · set frequency/duty: FDPWM()

Function prototype

```cpp void FDPWM(uint8_t pin, int32_t intHz, float Duty); ```

FDPWM(pin, intHz, Duty) specifies the frequency (Hz) and duty cycle (%). Output 1kHz at 50% duty on D5. D5·D2·D3 share Timer3, and D6·D7·D8 share Timer4; specify the same frequency for outputs on the same timer. There is no separate FPWM() function; use FDPWM(pin, hz, 50.0f) for 50% duty output.

```cpp void setup() {

PWM_RESET();  // Stop PWM timers and reset their modes
FDPWM(5, 1000, 50.0f);  // Output 1kHz at 50% duty on D5

}

void loop() { } ```

#### Function example · output a specified pulse count: NPWM\_BEGIN(), NPWM()

Function prototype

```cpp void NPWM_BEGIN(uint8_t pin, uint32_t intHz, float Duty, uint32_t N); void NPWM(uint8_t pin); ```

Use NPWM\_BEGIN() to prepare 100 pulses at 1kHz and 50% duty on D5, then run NPWM() on every loop() iteration to handle output and completion. Do not insert delay(). D5·D2·D3 share Timer3, and D6·D7·D8 share Timer4; do not combine this with other outputs on the same timer.

```cpp void setup() {

PWM_RESET();  // Stop PWM timers and reset their modes
NPWM_BEGIN(5, 1000, 50.0f, 100);  // Prepare 100 pulses at 1kHz, 50% duty on D5

}

void loop() {

NPWM(5);  // Process the prepared pulse output and completion

} ```

#### Function example · stop/resume channel output: PWMOFF()

Function prototype

```cpp void PWMOFF(uint8_t pin, bool POff); ```

PWMOFF(pin, true) sets the channel stop flag; false clears it. Call FDPWM() immediately after setting the flag to apply it to the output connection. Turn D5 on for 2 seconds and off for 2 seconds; after stopping, hold LOW with digitalWrite(). This stop flag does not apply to NPWM().

```cpp void setup() {

PWM_RESET();  // Stop PWM timers and reset their modes

}

void loop() {

PWMOFF(5, false);  // Clear the stop state of D5
FDPWM(5, 1000, 50.0f);  // Apply the cleared flag and start 1kHz, 50% output
delay(2000);

PWMOFF(5, true); // Set the stop state of D5

FDPWM(5, 1000, 50.0f);  // Apply the stop flag and disconnect PWM output
digitalWrite(5, LOW);
delay(2000);

} ```

#### Function example · stop/reset PWM timers: PWM\_RESET()

Function prototype

```cpp void PWM_RESET(); ```

PWM\_RESET() resets the Timer1·Timer3·Timer4·Timer5 control registers and counters. Output 1kHz on D5 for 2 seconds, then stop all timers. This also affects PWM and counters on the same timer. It does not also clear the PWMOFF() stop flag.

```cpp void setup() {

PWM_RESET();  // Stop PWM timers and reset their modes
FDPWM(5, 1000, 50.0f);  // Output 1kHz at 50% duty on D5
delay(2000);
PWM_RESET();  // Stop and reset all PWM on Timer1, Timer3, Timer4 and Timer5
digitalWrite(5, LOW);

}

void loop() { } ```

## Communication and Upload

Use the MP download cable to upload programs. RS-485 uses automatic direction control, so no separate control pin is needed to switch between transmission and reception.

### Example program · basic communication

Forward characters between Serial(115200bps) and RS-232 Serial1(9600bps, 8-N-1). Check the free space in the transmit buffer with availableForWrite(). Serial2 is RS-485 and Serial3 is TTL UART; when using those terminals, replace Serial1 in the example with the corresponding object.

```cpp // Serial Monitor via MP download cable ↔ RS-232 Serial1 void setup() {

Serial.begin(115200);
Serial1.begin(9600);  // Also configure the other device for 9600 bps, 8-N-1

}

void loop() {

if (Serial.available() && Serial1.availableForWrite()) {
  Serial1.write(Serial.read());
}
if (Serial1.available() && Serial.availableForWrite()) {
  Serial.write(Serial1.read());
}

} ```

### Example program · I²C communication

Use Wire to scan addresses 0x08~0x77 and display responding addresses every 3 seconds. Do not run this simultaneously with encoder/interrupt examples that use SDA·SCL.

```cpp #include <Wire.h>

void setup() {

Serial.begin(115200);
Wire.begin();
Wire.setClock(100000);

}

void loop() {

uint8_t found = 0;
for (uint8_t address = 0x08; address <= 0x77; address++) {
  Wire.beginTransmission(address);
  const uint8_t result = Wire.endTransmission();
  if (result == 0) {
    Serial.print(F("I2C: 0x"));
    if (address < 16) Serial.print('0');
    Serial.println(address, HEX);
    found++;
  }
}
Serial.print(F("Devices: "));
Serial.println(found);
delay(3000);

} ```

### Example program · Modbus RTU communication

Related built-in functions

#### Function example · Modbus RTU Slave: ImodbusRTUMem(), ImodbusRTUAdr(), ImodbusRTUInit(), ImodbusRTU()

Function prototype

```cpp void ImodbusRTUMem(uint16_t m_size, uint16_t d_size); void ImodbusRTUAdr(uint16_t m_offset, uint16_t d_offset); void ImodbusRTUInit(HardwareSerial& serialPort, uint8_t slaveId, long baudrate); void ImodbusRTU(); ```

Store the D22 state in M[0] and the raw A0 reading (0~1023) in D[0] for the other device to read. Configure RS-232(Serial1), station 1, 9600bps, 8N1. Read M[0] with FC01, start address 0, quantity 1 bit; read D[0] with FC03, start address 0, quantity 1 word. Addresses are zero-based on-wire addresses. Call the communication function on every loop() iteration. This example does not control outputs.

M and D are shared global memory provided by the core. Run this sketch on its own. When combining protocols, do not allocate the shared memory more than once. For RS-485 terminals, replace Serial1 with Serial2; for UART terminals, use Serial3.

```cpp unsigned long lastPrint = 0; bool memoryReady = false;

void setup() {

Serial.begin(115200);
ImodbusRTUMem(8, 8);  // Allocate 8 M bits and 8 D words
ImodbusRTUAdr(0, 0);  // Set the M and D communication start addresses to 0
ImodbusRTUInit(Serial1, 1, 9600);  // Start RS-232 at station 1, 9600bps
memoryReady = (M != nullptr && D != nullptr);
if (!memoryReady) Serial.println(F("Memory allocation failed"));

}

void loop() {

if (!memoryReady) return;
M[0] = digitalRead(22);
D[0] = analogRead(A0);
ImodbusRTU();  // Process incoming Modbus RTU requests

if (millis() - lastPrint >= 1000) {

  lastPrint = millis();
  Serial.print(F("M[0]: "));
  Serial.print(M[0]);
  Serial.print(F(", D[0]: "));
  Serial.println(D[0]);
}

} ```

#### Function example · Modbus RTU Master: ImodbusRTUmasterInit(), ImodbusRTUmaster()

Function prototype

```cpp void ImodbusRTUmasterInit(HardwareSerial& serialPort, long baudrate, uint8_t config); uint8_t ImodbusRTUmaster(HardwareSerial& serialPort, uint8_t slaveId, uint8_t functionCode, uint16_t address, uint16_t quantity, uint16_t* data, uint16_t timeoutMs = 100); ```

Read one holding register from the remote slave over RS-232(Serial1) every 1 second. Configure the other device for station 1, 9600bps, 8N1, FC03, and on-wire start address 0. The response is stored in received[0] and displayed only on success. Error codes are displayed in hexadecimal. This is a separate sketch from the slave example above and uses a receive array instead of M/D memory. For RS-485 terminals, replace Serial1 with Serial2; for UART terminals, use Serial3.

```cpp unsigned long lastRequest = 0; uint16_t received[1];

void setup() {

Serial.begin(115200);
ImodbusRTUmasterInit(Serial1, 9600, SERIAL_8N1);  // Start RS-232 as a Modbus master

}

void loop() {

if (millis() - lastRequest < 1000) return;
lastRequest = millis();
const uint8_t result = ImodbusRTUmaster(Serial1, 1, 3, 0, 1, received, 200);  // Read 1 word at address 0 from station 1, timeout 200ms

if (result == IMODBUS_RTU_SUCCESS) {

  Serial.print(F("Register 0: "));
  Serial.println(received[0]);
} else {
  Serial.print(F("Modbus error: 0x"));
  Serial.println(result, HEX);
}

} ```

### Example program · LS Industrial Systems Cnet communication

Related built-in functions

#### Function example · LS Industrial Systems Cnet SLave: ICnetMem(), ICnetAdr(), ICnetInit(), ICnet()

Function prototype

```cpp void ICnetMem(uint16_t m_size, uint16_t d_size, uint16_t r_size = 100); void ICnetAdr(uint16_t m_offset, uint16_t d_offset, uint16_t r_offset = 0); void ICnetInit(HardwareSerial& serialPort, uint8_t slaveId, long baudrate); void ICnet(); ```

Store the D22 state in M[0] and the raw A0 reading (0~1023) in D[0] for an HMI to read. Configure the other device for LS Industrial Systems Cnet, RS-232, station 1, 9600bps, 8N1. Read the bit at %MX00000(M[0]) and the word at %DW0(D[0]). Call the communication function on every loop() iteration. This example does not control outputs.

M, D, and R are shared global memory provided by the core; this example does not use R. Run this separately from the Modbus example. When combining protocols, do not allocate the shared memory more than once. For RS-485 terminals, replace Serial1 with Serial2; for UART terminals, use Serial3.

```cpp unsigned long lastPrint = 0; bool memoryReady = false;

void setup() {

Serial.begin(115200);
ICnetMem(8, 8, 0);  // Allocate 8 M bits and 8 D words; R is unused
ICnetAdr(0, 0, 0);  // Set the M and D communication start addresses to 0
ICnetInit(Serial1, 1, 9600);  // Start RS-232 at station 1, 9600bps
memoryReady = (M != nullptr && D != nullptr);
if (!memoryReady) Serial.println(F("Memory allocation failed"));

}

void loop() {

if (!memoryReady) return;
M[0] = digitalRead(22);
D[0] = analogRead(A0);
ICnet();  // Process incoming LS Cnet requests

if (millis() - lastPrint >= 1000) {

  lastPrint = millis();
  Serial.print(F("M[0]: "));
  Serial.print(M[0]);
  Serial.print(F(", D[0]: "));
  Serial.println(D[0]);
}

} ```

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