Input Leakage Current (LED Indicator Switch)

What does INPUT-LKG-C4 mean?

A leakage current from a switch with an LED indicator causes the input signal to remain ON even when the switch is physically OFF. This occurs because the leakage current (e.g., 2.82mA at 24VDC for RX40C7) exceeds the input module's OFF current threshold (e.g., 2.0mA), preventing the input from reliably turning off.

• Leakage current from the LED indicator switch is higher than the input module's specified OFF current threshold (e.g., 2.0mA for RX40C7).
• The input resistance of the module (e.g., 3.3kΩ for RX40C7) is insufficient to drop the residual voltage below the OFF state requirement.

Click steps to track your progress.

1. 1

   Connect a resistor in parallel across the input terminals to ensure the current flowing into the module falls below the OFF current threshold. For an RX40C7 with 24VDC supply and 2.82mA leakage, use an 8.2kΩ, 1/2W resistor.

2. 2

   Verify that the added resistor ensures the OFF voltage at the RX40C7 terminal is lower than 8V, confirming the input can reliably turn off.