The SIM100MLP is the first high-voltage isolation monitoring device for EV/HEVs capable of operating correctly even when the battery is active, and experiencing large voltage variations, no variations, or even if the battery is not connected. The SIM100MLP continuously monitors the isolation resistance between a vehicle’s IT (Isolated Terra) power system and chassis for deterioration of isolation and potentially dangerous levels of leakage current. The module detects not only resistive leakages but also capacitively stored energy that could be harmful to human operators.

Usability
• Reports battery voltage
• Reports uncertainty for all measured and calculated values
• Provides nonvolatile storage for the value of the maximum (design) voltage of the battery (used in calculations of the isolation resistance and stored energy)
• Provides nonvolatile storage for calibration of the voltage measurements and other parameters

Performance
• Measures voltage of each battery terminal with reference to chassis
• Reports accurate estimates of the isolation status while the battery is having large voltage variations
• Initializes in under 6 seconds
• Detects an insulation value change in less than 5 secs
• Measures and reports the value of capacitance from each battery terminal to chassis
• Calculates and reports the energy stored by the total capacitance between the battery and chassis
• Provides high immunity to common-mode noise that can be present on the battery terminals

Safety
• Measures and reports modeled leakage resistances per model adapted by the safety standards ISO6469-1, FMVSS §571.305, and others
• Reports calculated isolation resistance in Ω/V per requirements of the safety standards
• The unit continuously monitors both the connections of the voltage sense lines to the battery terminals and its own connection to the chassis, reporting any inadequate connections in either case
• Provides built-in galvanically isolated and intrinsically leakage-safe excitation source
• A single CAN message provides sufficient information for determination of the safety status of the system
• Warning and Fault alerts provided in the STATUS byte for low insulation resistance values