Insulation Resistance Meter

The MSIS system measures the insulation of a Signalling System (IS) cable to Earth or to Equipotential Bar of the power supply system. The system is able to detect insulation anomalies.

It is possible to carry out the measurement automatically, manually or remotely. The system generates a proper alarm in case the measurement exceed the preset threshold.

The MSIS can also measure other electrical values of the cable, such as voltage (a.c. and d.c.), frequency, ripple. It generates specific alarms in case the measured values exceed the preset thresholds. The system allows to transmit measurement data and alarms to a remote Centralized Diagnostic System (SDC).

The MSIS system guarantees a high level of reliability required within the typical railway signalling environments (sentry station, station) taking into account different sources of environmental stresses (vibration, temperature range, over voltages, etc.) according to the IS 402 Railway Regulation (Installation environment A5).

This product complies with the RFI DI IS 228 specification (02/1992 edition).

The system is housed in a 19 inch rack, using a sub-rack with a height of 3U MSIS-CEST (cat/prog 820/9520). The sub-rack houses 1 power supply module MSIS-ALIM (cat/prog 820/9540) and 1 to 6 independent modules MSIS-ISO (cat/prog 820/9510). Where such a rack is not available the sub-rack can be housed in an appropriate box MSIS-BOX (cat/prog 820/9550).


The system has modular design in order to be easily adapted to specific customer requirements.


The MSIS Auto Diagnostics  (auto-test of the measurement channels) is able to detect anomalies in the internal functions with the generation of a proper Alarm in case of breakdown.


The MSIS has 2 output relay contacts (N.C.). One indicates an alarm of low insulation and the other indicates an internal breakdown. Both alarms are also displayed by the specific LED.


Each MSIS-ISO module is able to measure on Signalling System powered or not powered cables. The cables can be supplied by: D.C.: 24Vdc, 48Vdc, 60Vdc, 144Vdc A.C.:80Vac, 120Vac, 150Vac, 220Vac.