Setup & Installation 2
Digital Inputs:
Modules should never be installed while power is applied to the BASIC I/O.
With the exception of IDC5S digital input modules, input sensing current comes from a source external to the BASIC I/O. IDC5S input modules provide their own current for sensing contact closures. They can be DESTROYED if an external source is used.
The IDC5 and IDC5D input modules are polarity sensitive and operate only when the + terminal is more positive with respect to the - terminal. Polarity does not affect the performance of the IAC5, IAC5A, or the IDC5S input modules.
Because the field side of input modules are totally isolated from each other, like polarities can be wired common to make use of a single power supply.
The wiring and operation of digital input modules can be verified by closing the individual input sensing contacts and observing the changes on the module status indicators. They are on when the module circuit is energized. Their wiring can also be verified at the host by issuing a configure as input instruction, setup H, followed by a read all modules instruction, digital M. See software protocol manual, or quick reference card for instruction details.