Connection of the outputs
Circuit examples for output to A. The same principles apply to output B.
EL2521
The outputs A and B of the EL2521 can be used in different connection modes. An integrated DC/DC converter supplies the output stage of the two channels, A and B, with an electrically isolated 5 V power supply.
- Connection to RS422 receiver
The output can be operated as an RS422 output. The circuit generates the necessary differential signals.
- Connection to optocoupler (without external supply voltage)
The outputs can be used for direct connection of an optocoupler. The output stage supplies the necessary output current using an internal 5 V supply voltage.
EL2521-0024, EL2521-0124
The operation with an external supply voltage depends on the hardware version of the terminal:
- Connection to optocoupler (with external supply voltage)
For connection to inputs with a large input resistance, an external supply voltage (up to 24 V) can be used with the EL2521-0024 in order to create the necessary current.
Note | |
EL2521-0124 ground potential In the case of the EL2521-0124 the outputs -A and -B must be connected to the signal ground (pin 4) in order to avoid damage to the terminal (see fig. EL2521-0124 pin assignment and sample connection)! |
EL2521-0025
Note | |
Logic reversal with the EL2521-0025 When connecting the EL2521-0025, observe the logic reversal with the wiring (see fig. EL2521-0025 pin assignment and sample connection)! |
- Connection to optocoupler (with external supply voltage)
For connection to inputs with a large input resistance, an external supply voltage (up to 24 V) can be used with the EL2521-0025 in order to create the necessary current. Due to the logic reversal, the positive voltage for driving the output current is to be connected to pin 5 or pin 6.
