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en-us_commands:reference:ianalogwrite2f

IanalogWrite2f()

IanalogWrite2f() converts a user floating-point value to the 4~20mA output range.

IanalogWrite2f command operation flow

void IanalogWrite2f(uint8_t ch, float min, float max, float value)

Commands

Command Arguments Return Value Operation
IanalogWrite2f(ch, min, max, value) uint8_t ch — MPINO: analog pin such as A0; MPAINO: overall module channel number starting at 0
float min
float max
float value — Output value expressed in the min ~ max range
void Converts a user floating-point value to the 4~20mA output range.

Example

Connect a Y output module to MPAINO-8A8R(T) and select Analog Output Module → Y. Set the CH0 DIP switch to OFF and measure the 4–20mA output at I+ and .

void setup() {}
 
void loop() {
  IanalogWrite2f(0, 0.0F, 100.0F, 25.0F);  // Scale 25% to the 4–20mA range and output about 8mA.
  delay(500);
}

Precautions

  • Set the MPAINO Y module CH0 DIP switch to OFF and connect the 4–20mA output to I+ and .
  • 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/ianalogwrite2f.txt · Last modified: by 127.0.0.1

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