• Monitors insulation for AC/DC control circuits (0-300 V).
• Two adjustable response values with preset function for automatic parameter setting.
• Includes connection monitoring, LEDs for status indication, and test/reset buttons.
• Equipped with two alarm relays and selectable fault memory behavior.
• Features a multi-functional LC display and adjustable response delay.

The ISOMETER® IR425 series monitors insulation resistance in unearthed AC/DC control circuits. It operates independently of DC components and can monitor de-energized systems with an external supply voltage.

• Suitable for industrial sectors, mechanical engineering, power plants, elevators, and automation systems.
• Complies with standards such as DIN EN 60204-1 and DIN VDE 0100-725.

The device displays the measured insulation resistance and triggers alarms if values fall below preset thresholds. It distinguishes between AC and DC faults and retains alarm states if the fault memory is enabled.

Automatically checks connections every 24 hours or upon pressing the test button. Displays error codes for connection faults.

Automatically sets response values based on the nominal system voltage upon initial connection.

Utilizes the AMP measuring principle.

• Complies with DIN EN 61557-8, EN 61557-8, and IEC 61557-8.

• Rated insulation voltage: 250 V, impulse voltage: 4 kV.
• Supply voltage varies by model, with a frequency range of 15-460 Hz.
• Response values for alarms range from 1-200 kΩ.
• Operating temperature: -25 to +55 °C.
• Connection options include screw-type and push-wire terminals.

Available in different models with varying supply voltage specifications and terminal types.