Overview of functions 
  5.2 Monitoring functions 
SIMOCODE pro 
System Manual, 05/2019, A5E40507475002A/RS-AD/004 
49 
5.2  Monitoring functions 
Detailed description: See Chapters "Monitoring functions" and "Logic blocks" in the manual 
Parameterizing SIMOCODE pro 
(https://support.industry.siemens.com/cs/ww/en/view/109743958
).  
Current limit monitoring 
Current limit monitoring is used for process monitoring. This enables incipient anomalies in 
the system to be detected in good time. If a current limit is exceeded but still below the 
overload limit, it can, for example, indicate a dirty filter on a pump, or an increasingly 
sluggish motor bearing. If the current limit is undershot, it can be the first sign of a worn-out 
drive motor belt.  
Ground-fault monitoring  
Residual current monitoring relays are used in industry to 
●  Protect systems from damage caused by residual currents 
●  Prevent production losses caused by unplanned downtime 
●  Perform maintenance to meet all demands. 
Basic units have: 
●  An internal ground-fault monitoring system: For motors with a 3-wire connection, the 
basic unit calculates a possible fault current/ground-fault current from the total current via 
a current measuring module or a current / voltage measuring module. Internal 
ground-fault monitoring is only possible for motors with a 3-phase connection in networks 
that are either grounded directly or grounded with low impedance.  
●  External ground-fault monitoring in SIMOCODE pro S and SIMOCODE pro V 
4) 
: The 
external ground-fault monitoring using residual current transformer 3UL23 and  
ground-fault module is normally used in the following cases: 
–  in cases in which power systems are grounded with high impedance 
–  in cases, in which precise detection of the ground-fault current is necessary, for 
example, for condition monitoring. 
A ground-fault module can be used to create an additional input on the 
SIMOCODE pro V and SIMOCODE pro V PN GP basic units to connect a 3UL23 residual 
current transformer. 
A multifunction module can be used to create an additional input on the 
SIMOCODE pro S basic unit to connect a 3UL23 residual current transformer.  
With ground-fault detection using the 3UL23 residual current transformer, it is possible to 
determine the precise residual current as a measured value, and to define freely 
selectable warning and trip limits in a wide range from 30 mA - 40 A. 
See also Chapter "External ground-fault monitoring with 3UL23 residual current 
transformer" in the manual Parameterizing SIMOCODE pro 
(https://support.industry.siemens.com/cs/ww/en/view/109743958
).