Outputs with manual override

The M215 and M325 modules feature manual override buttons at the front panel. Every output may be overriden to ON or OFF separately. A long push (> 1.5 s) of the button switches from automatic (controlled over the bus) mode to manual mode, which is indocated by the yellow LED (symbol of a hand). Short pushes (< 1 s) in the manual mode toggle between ON and OFF. The state is indicated by a green LED (digital output symbol). Another long push switches back to automatic mode, the yellog LED goes off and the output is controlled by the commands over the bus (from the process station)

Manual mode and manual output state are saved in EEPROM and are kept even after power outage.

M325 module with buttons and LEDs for manual override

The output states (auto/man, off/on) are available as Modbus registers and can be read by the process station to be e.g. displayed in the SCADA or indicated as an alarm. It is not possible to switch the outputs to manual or auto over the bus (which would not make sense for the manual functionality). To control the outputs directly from SCADA (and to override the process logic in the PLC) there are other SoftPLC functions, however, the manual override directly at the I/O module is that of the highest priority.