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en-us_commands:reference:ianalogread2

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IanalogRead2()

IanalogRead2() converts the 4~20mA input value to the specified integer range.

IanalogRead2 command operation flow

int32_t IanalogRead2(uint8_t ch, int32_t min, int32_t max)

Commands

Command Arguments Return Value Operation
IanalogRead2(ch, min, max) uint8_t ch — MPINO: analog pin such as A0; MPAINO: overall module channel number starting at 0
int32_t min
int32_t max
int32_t Converts the 4~20mA input value to the specified integer range.

Example

void setup() {
  analogReference(EXTERNAL);  // If required by the MPINO product
  Serial.begin(115200);
}
 
void loop() {
  int32_t percent = IanalogRead2(A2, 0, 100);  // Map the 4–20mA input value to the specified integer range.
 
  if (percent == ANALOG_READ2_ERROR) {
    Serial.println("4-20mA wire break or input error");
  } else {
    Serial.println(percent);
  }
 
  delay(500);
}

Precautions

  • Set the module DIP switches and wiring for 0~20mA current I/O.
  • An input of approximately 3.6~4.0mA returns the normal value 0; inputs below 3.6mA return an error value.
  • Error values help detect open circuits. The user must implement final alarms and safety actions in the program.
  • IanalogRead2() and IanalogRead2f() also return 65535 on error, rather than a user-range value. Check for errors before using the result.
  • The full int32_t range is available for min~max in IanalogRead2(), but if the normal range includes 65535, it cannot be distinguished from an error value.
  • analogRead2Avgf() uses state and a buffer separate from analogRead2Avg(). Using both increases SRAM usage.
  • If samples is 0 or memory allocation fails in analogRead2Avgf(), it returns the current valid corrected value as a float.
  • On MPINO, do not use analogRead2() on voltage/NTC channels that are not 4~20mA inputs.
  • For MPINO products requiring analogReference(EXTERNAL), set it first in setup().
  • IanalogWrite2() and IanalogWrite2f() are convenience outputs dedicated to 4~20mA. Avoid alternating them with IanalogWrite() on the same channel.
  • The analog output circuit requires an external 12~24V supply. USB power alone may not provide normal output.
  • Verify actual current input/output with measuring instruments after preparing a test product.

Built-in Commands in the Same Category

en-us_commands/reference/ianalogread2.1788796396.txt.gz · Last modified: by 127.0.0.1

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