Pilz S1MS Data Sheet
Electronic monitoring relays PMDsrange
Thermistor monitor
S1MS
The thermistor monitoring relay S1MS is used as a protection device in temperature monitoring 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 versions available for AC operation and one for AC and DC operation.
A temperature sensor is connected to the S1MS measuring circuit. If the temperature exceeds 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 auxiliary 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
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Electronic monitoring relays PMDsrange
Thermistor monitor
S1MS
Internal wiring diagram
Measuring circuit
* Insulation between the non-marked area and the relay contacts: Basic insulation (overvoltage category III), safe separation (overvoltage category II)
1003090-EN-01 2013-09
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Electronic monitoring relays PMDsrange
Thermistor monitor
S1MS
Timing diagram
11 - 14
+
21-24
Legend:
} U
Supply voltage
B
} R
} R
} R
Response value
on
Release value
off
PTC resistor
th
Connection example
cannot be stored
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