Field Voltage Too High

What does Diag 2 Flash 6 mean?

The voltage supplied to the power contacts of the terminal is too high. This could be due to a consistent overvoltage on the power contacts or brief external influences such as switching off contactors causing voltage spikes. An overvoltage can damage internal components of the terminal and compromise its safe operation.

• Malfunctioning 24VDC power supply unit (PSU) delivering sustained output voltage above 28.8VDC.
• Inductive kickback or voltage spikes generated by switching off large inductive loads (e.g., contactors, solenoids) on the same 24VDC field circuit.
• Incorrectly wired power supply, potentially connected to a higher voltage source than 24VDC (e.g., 48VDC).
• Faulty voltage regulator or suppressor circuit within the terminal module, misinterpreting acceptable voltage levels.
• Interference from external noise sources on the 24VDC supply lines, causing transient overvoltages not suppressed by module filtering.

Click steps to track your progress.

1. 1

   1. Using a calibrated multimeter, measure the 24VDC field supply voltage directly at the input terminals of the affected module. Voltage must be within 20.4VDC to 28.8VDC.

2. 2

   2. Measure the output voltage of the 24VDC power supply unit (PSU) at its terminals. If it consistently reads above 28.8VDC, replace the PSU.

3. 3

   3. Install appropriate suppression devices (e.g., flyback diodes, RC snubbers) across the coils of inductive loads connected to the same 24VDC field circuit.

4. 4

   4. Verify the correct voltage selection for the 24VDC power supply and ensure no incorrect wiring from higher voltage sources by checking schematic diagrams.

5. 5

   5. Disconnect the terminal from the field power, power up the system, and measure the 24VDC supply under load, monitoring for transient peaks using an oscilloscope (e.g., Fluke ScopeMeter).