West Control Solutions Pro-EC44 - Manual (Page 34)

Pro-EC44 2-Loop Graphical Profile Controller & Recorder
Pro-EC44 Product Manual - 59540-1 October 2013 Page 27
Option C Connections
Option C offers a factory fitted multiple digital input option. The board also accommodates
the USB port if that is option is fitted. The USB port does not have connections on the rear
terminal, it is accessed via the front panel.
Option C Connections
– Multiple Digital Input Module
If the Multiple Digital Input option is fitted, the connections are as illustrated. The 8 opto-
isolated inputs each have a positive input terminal and share a common negative terminal.
The inputs are held high with internal pull-up resistors, so may be connected to either voltage
free contacts (e.g. from a switch), or TTL compatible signals:
Logic High = Open contacts
(>5000Ω) or 2 to 24VDC signal.
Logic Low = Closed contacts (
<50Ω) or -0.6 to +0.8VDC signal.
Figure 41. Option C - Multiple Digital Inputs C1 to C8