1732E ArmorBlock inputs sink and not source

[kaiser_will 65]

I am looking at going with 1732E ArmorBlock, talking Ethernet/IP to a MicroLogix1400 PLC, but was surprised to see the only weld block selection is for sinking/NPN inputs (1732E-IB16M12W). I found this strange as most US controls inputs are sourcing. Getting over this is not a big deal, but there is a big difference in troubleshooting sink or sourcing inputs. Has anyone had experience with the ArmorBlock line, possibly understanding the reasoning? Edited 7 Jul 2010 by kaiser_will

[kaiser_will 65]

Digging in further, it appears that A-B's interpretation of sink-source is opposite. Voltage On state (input, nominal) = 24VDC is Source, not Sink. Have others run into this Source-Sink issue before and found A-B's interpretation to be counter to the masses?

[paulengr 44]

No, and this is the reason that you should stop using the terms "sourcing" and "sinking". In fact even within the same manufacturer, they frequently mix these terms up. It is far better to use the terms NPN and PNP which refer to the transistor drivers themselves and then you can avoid this complication.