Issue
- Is it needed to connect DC voltage to trigger the DI of the 301 and 421A
- What is the max current/voltage that a DI point can handle.
Environment
Xenta 301, Xenta 302, Xenta 4xx
Cause
The inputs on the Xenta 300 and 4xx are active inputs from the terminals X1, U1 etc. Meaning the terminal is at high voltage when open. For a UI (act as a DI) channel, the voltage across open contact is approximately 20 V DC, and for a XI channel, the voltage across open contact is approximately 33 V DC.
To activate the digital input, engineer needs to connect the signal to M ( = 0 volt) terminal, so current flows FROM the X1 to M. So basically we expect a switch that connects M and X1 (U1).
Resolution
No you only need a switch that connects M0 to X1 or U1 (or other digital, universal input).
Note: It is recommended to have a non-voltage dry point relay switch to protect the digital input on the controller and IO module.
