AERMEC MCR Manuel D'utilisation page 28

DL3: TTL SERIAL STATUS DISPLAYS
The LED DL3 has the function of indicating whether the TTL serial line is working properly, specifically:
1. For MCR master modules (they have a direct connection to the user interface), the DL3 LED flashes for each Modbus command received correctly from the user interface
(VMF-E4X, VMF-E3 or VMHI);
2. For slave MCR modules (they are not associated with any user interface), the DL3 LED flashes for each Modbus command correctly received from the master controller of
the TTL network.
E4X
1 2 3 4
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Master
Slave TTL
Slave
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