Important: The AD Input Modules' inputs are not isolated, so please be sure to not provide voltage or current in excess of the specified ranges. Doing so could cause permanent damage.

The MD-HADIN4's sampling frequency is 240ms per channel, so sampling all 4 channels will take approximately 960ms. Therefore, it is unnecessary read more than once every 960ms, as it too will always return the same value.

When the system is first powered on, all four channels are scanned once. Reading at this time will return an invalid value. Please allow at least 960ms from the time the system is powered on before reading and data.

The MD-HADIN4 has the benefit of a higher resolution than the MD-ADIN4, but takes longer to do the conversion. Therefore, the MD-HADIN4 may not be suitable for high frequency signals.

Read two 16-bit words from the MD-HADIN’s starting address to obtain the full 32-bit value. The data will be returned most significant word first.

The value returned from the MD-HADIN can be interpreted with the following algorithm:

unsigned int rawData = 0; // Raw 32-bit value from the MD-HADIN
long value = rawData;
 
if ((rawData & 0x80000000) != 0) // If most significant bit is set
{
    value = (rawData - 0x80000000) * -1;
}
 
if (value == -111111)
{
    // Value is below the lower bound (e.g. below 1V when 1-5V mode is selected).
}
else if (value == 222222)
{
    // Value is above the upper bound. (e.g. above 5V when 1-5V mode is selected).
}
else
{
    // Value is between 0 and 100,000
}

Each module has 4 channels, each with its own unique Modbus address.

On the front of the module, there is a rotary switch labeled ID, that is used to select the Modbus slave address for the module. When installing multiple modules of the same type, the ID for each module should be unique.

Rotary switch position 0 corresponds to Modbus slave address 10. If the ID is changed after the module is powered on, it must be power cycled for the new ID to take effect.

MODPORT