InValue Error

What does FB ENVELOPE Value 3 mean?

A general error related to the input value (InValue) has occurred within the FB Envelope function block. This could be due to invalid input data, a fault in the input signal path, or internal processing issues. This fault will lead to the FB entering a safe state, halting operation.

• Invalid input data from a connected safety device due to communication errors (e.g., corrupted FSoE telegram).
• Fault in the analog input signal path, such as an open circuit (e.g., sensor wire to terminal A1-1 broken) or short circuit.
• Analog input module hardware failure (e.g., internal diagnostic error on EL3102 module at slot 3).
• Incorrect scaling or data type conversion applied to the 'InValue' within the PLC program before it reaches the FB Envelope (e.g., DINT to REAL conversion error).

Click steps to track your progress.

1. 1

   1. Monitor the raw 'InValue' in the TwinCAT System Manager (or equivalent diagnostic tool) for erratic or out-of-range readings.

2. 2

   2. Measure the voltage or current directly at the analog input terminals (e.g., AI_01) on the safety I/O module to confirm signal integrity.

3. 3

   3. Verify the sensor's health and output (e.g., 4-20mA, 0-10V) at its terminals.

4. 4

   4. Check the configuration of the analog input module (e.g., EL3102, channel 1) for correct input range and scaling parameters.

5. 5

   5. Power cycle the safety I/O module (e.g., EL3xxx) to reset its internal diagnostics.