Connection On Com20 For 3Vl; Com20 Pin Assignment - Siemens Library SENTRON 3WL Function Manual

Configuration Manual

4.3 Connection on COM20 for 3VL

4.3 Connection on COM20 for 3VL
4.3.1

COM20 pin assignment

The COM20 must be supplied with 24 V DC for operations and this must be supplied to the
terminals A2 (ground) and A1 (+). This voltage is looped-through via the communication
cable to the ETU (trip unit) of the 3VL circuit-breaker such that this is also operated when the
main contacts are open. Without this supply the ETU would not be able to communicate
diagnosis information, such as the reason for the last trip, if there were no self-supply.
Unlike COM10, the auxiliary and alarm switches are not wired to the COM20, but directly to
the ETU, and the communication status forwarded to COM20. The following diagram shows
the principle of the connection between the COM20 and a SENTRON VL including the LEDs
and the PROFIBUS write protection DPWriteEnable.
Figure 4-5
130
COM20 connection to SENTRON VL
Library SENTRON 3WL / 3VL for SIMATIC PCS 7
Function Manual, 11/2008, A5E02316914A-01