32-channel Isolated Digital Input Module with 16-bit Counters. The I-87040W/I-87040PW offer 32 channels for digital input, each of which features photocouple isolation. Either sink- or source-type input can be selected via wire connections. All channels are able to be used as 16-bit counters and 32 LED indicators that can be used for monitoring DI channel status are also provided, together with 4 kV ESD protection and 3750 VDC intra-module isolat..