ZIEHL MS 220 DA, Operating Instructions Manual

Page: 36 / 48

3.1.4 Overview of Functions
The MCB 112 VLT PTC Thermistor option is a thermistor monitoring unit with integrated safe isolation and sensor circuit monitoring. The output X44/12
is connected to the FC 302 Safe Stop input (Terminal 37). For more details regarding the use of the Safe Stop function, see section 4.1.1
Particular
instructions for EN 61508 category SIL 1 and 2
At normal operation the output X44/12 is "High = 1". In case of motor over temperature it changes to "Low = 0" and activates Safe Stop. The output
changes back to "High = 1" when the temperature has fallen below the critical temperature level. This means that the tripping device has removed its
request for Safe Stop (however, another safety device may still require safe stop to be enabled). If safe stop is configured for Alarm (default), a manual
reset is required before safe stop is deactivated.
In case of short circuit of sensor or wiring, the output will also change to "Low = 0" and activate Safe Stop. The Safe Stop input on the FC 302 can be
connected to more signals at the same time, meaning Safe Stop can be activated by other external signals. In that case output X44/10 can be used to
identify if the alarm originates from the thermistor or another external signal.
In the FC 302 the following parameters must be set:
• Par 5-19: Safe Stop input must be configured to the relevant functionality including identification if other signals are connected.
• A digital input must be set to "PTC Card 1" [80] for the output X44/10 to identify the origin of the Safe Stop signal.
Illustration 3.2: Description of function
1) Short circuit
2) Warning: the trigger is not stored and is not zero-voltage safe.
MCB 112 VLT ® PTC Thermistor Option
3 Introduction to MCB 112 VLT PTC Thermis-
tor Card
MG.33.V2.02 - VLT ® is a registered Danfoss trademark
11
3