Shall the terminal 16 of the PCD2/3.W745 be connected to ground?

FAQ #100604

 

Reason for the terminal 16 (GND)
As the W745 is galvanically separated (the separation is from all terminals against the PCD I/O bus and not between the terminals) there is no defined ground level of the terminals. This leads to floating levels on the terminal side. In order to eliminate this floating level the terminal 16 is present for a connection against the common sensor ground.

 

When do I have to connect terminal 16 to GND?

• The terminal 16 should be connected to ground if no sensor does have an internal connection to the ground level. This is the case for common TC sensor or Pt/Ni sensors. In this case, connect the terminal 16 to ground.

• The terminal 16 should not be connected to ground if one or more sensors do have an own connection to ground (which is not recommended).

Note
The galvanic separation of the module is applied between the I/O bus of the PCD and the terminals of the W745. The terminals themselves are not separated galvanically agains each other (the GND of the inputs is connected on the module). The separation is designed for a voltage of 500 VDC.