EL3121 - Connection, display and diagnostics

Connection EL3121
Terminal point		Description	Internally connected with connection	Max. current carrying capacity *)
Name	No.	Description	Internally connected with connection	Max. current carrying capacity *)
+ Input 1	1	+ Input 1	-	40 mA
- Input 1	2	- Input 1	-	40 mA
GND	3	Signal ground for input 1	7, (high impedance, therefore potential equal but not current loadable)	40 mA
Shield	4	Shield (FE)	8; DIN rail	100 mA **)
n. c.	5	not connected	-	-
n. c.	6	not connected	-	-
GND	7	Signal ground for input 1	3, (high impedance, therefore potential equal but not current loadable)	40 mA
Shield	8	Shield (FE)	4; DIN rail	100 mA **)
) Constant and peak value *) Shield lines should be de-energized!

	GND connection points The GND connection points of the terminal are not connected internally directly, but via EMC protection components. Therefore, each analog encoder/sensor must be connected separately with 2 wires, even if the connection diagram of the terminal for the channels indicates a common ground (GND).

	Current carrying capacity of the input contacts The maximum permitted current on the signal-relevant terminal points (inputs, GND) is 40 mA (if applicable).

Notice

Terminal GND and system GND

The signal ground GND of this terminal is not internally connected to the negative power contact. This design allows GND to be connected to a ground other than the negative power contact "Power contact 0V" if necessary.
If disturbing potential differences occur, GND must be electrically connected to the system GND or another suitable ground.

	Overcurrent protection of the 20 mA inputs The current inputs are protected against damage by overcurrent by an internal current limitation, currents > 30 mA may occur. In the event of a fault, the current limiter must not be overloaded by a voltage > 30 V from the source device. Overcurrent is displayed in the process image as "Overrange". After occurrence, the error condition must be stopped immediately, the source device switched off or disconnected from the input terminal. If the error condition persists for a longer period of time, the internal terminal current limitation reduces the absorbed signal current for thermal reasons, depending on the ambient conditions also below 20 mA.

LEDs
LED	Color	Meaning
RUN*	green	This LED indicates the terminal's operating state *:
		off	State of the EtherCAT State Machine: INIT = initialization of the terminal or BOOTSTRAP = function for firmware updates of the terminal
		flashing	State of the EtherCAT State Machine: PREOP = function for mailbox communication and different standard-settings set
		single flash	State of the EtherCAT State Machine: SAFEOP = verification of the Sync Manager channels and the distributed clocks. Outputs remain in safe state
		on	State of the EtherCAT State Machine: OP = normal operating state; mailbox and process data communication is possible
ERROR**	red	Fault indication in the event of undershooting or overshooting of the measuring range
) If several RUN LEDs are present, all of them have the same function *) The error display shows the signal processing state for each channel