Datasheet
Electronic monitoring relays PMDsrange
Thermistor monitor
S1MS
Pilz GmbH & Co. KG, Felix-Wankel-Straße 2, 73760 Ostfildern, Germany
Telephone: +49 711 3409-0, Telefax: +49 711 3409-133, E-Mail: pilz.gmbh@pilz.de
1003090-EN-01 2013-09
1
The thermistor monitoring relay S1MS is used as a protection device in temperature moni-
toring circuits in accordance with EN 44081. It protects motors, generators, storage areas,
etc. from overheating.
Unit features
} Relay outputs:
2 auxiliary contacts (C/O)
} Measuring circuit for connecting a temperature sensor (PTC resistor)
} automatic reset
} LED as supply voltage indicator
} LED as fault indicator
Unit description
The thermistor monitoring relay is enclosed in an S-95 slimline housing. There are 5 ver-
sions available for AC operation and one for AC and DC operation.
A temperature sensor is connected to the S1MS measuring circuit. If the temperature ex-
ceeds a defined value, i.e. the resistance of the temperature sensor reaches the response
value, the output contacts switch.
Contacts 11-14 and 21-24 open, contacts 11-12 and 21-22 close. If the temperature then
falls again, i.e. the resistance of the temperature sensor reaches the release value, the aux-
iliary contacts automatically switch again. The unit is ready for operation.
Safety features
The unit meets the following safety requirements:
} Operates to normally energised mode
} Protection of the monitored unit is maintained in the following cases:
– Power failure
– Coil defect
– Open circuit