Used Digital Input Boards for Sale

Digital input boards read the on/off state of binary signals - TTL logic, relays, proximity sensors, limit switches, encoder edges - and present them to a host CPU or backplane bus. They are standard components in automated test equipment (ATE), industrial machine control, defense test stations, and data acquisition systems where you need to monitor dozens to hundreds of discrete signals simultaneously.

TTL inputs accept standard 0–5 V logic and are designed for board-to-board communication inside a clean electronics enclosure. High-voltage inputs accept 24 V or 48 V DC, which is the standard for industrial field wiring - sensors, solenoids, and proximity switches in factory environments typically run at these levels. The VMIC VMIVME-1111 and VMIVME-1150 are high-voltage boards. Optically isolated inputs add a physical electrical break between field wiring and the backplane, protecting against voltage spikes and ground loops. Choose isolation when inputs come from outside a well-controlled enclosure.

IndustryPack (IP) is a mezzanine module standard originally developed by GreenSpring, now under IEEE-1101.10. An IP module - roughly 2.5 × 3.9 inches - plugs into an IP carrier board, which in turn sits in a VMEbus, CompactPCI, or PXI chassis. The IP-UNIDIG, IP-Altera-TTL, IP-TTL48-8, and Acromag IP440A products sold here are IP modules. They require a compatible IP carrier (such as an Acromag IPAC-8 or SBS IP-EP series) to operate. If you do not already have a carrier, factor it into your purchase.

The VMIVME series from VMIC (now Abaco Systems) is the most widely deployed VME digital I/O family in US defense automatic test equipment. VMIVME-1111 (64-bit high-voltage input), VMIVME-1128 (128-bit high-voltage input), VMIVME-1150 (64-bit optically isolated input), and VMIVME-2528 (128-bit TTL I/O) appear routinely in legacy test stations for aircraft avionics, guided weapons, and ground vehicle electronics. The VMIVME-1184 adds Sequence-of-Events (SOE) time-stamping, which is required in power utility relay test systems.

PCI is the standard horizontal card slot in desktop and industrial PCs. CompactPCI (cPCI) uses Eurocard packaging with rugged press-fit connectors in a 19-inch rack chassis - designed for higher vibration tolerance and hot-swap capability in embedded industrial applications. The Adlink cPCI-7248 is CompactPCI. The Acces PCI-DIO-24H and PCI-DIO-72 are standard PCI cards. If your system is a standard PC tower or industrial PC with a PCI slot, use PCI; if it is a rack-mount cPCI chassis, use the Adlink cPCI card.

Abaco Systems (which acquired SBS Technologies, which acquired VMIC) provides the Abaco Software Foundation (ASF) driver package for Windows and Linux. VxWorks and LynxOS drivers from the SBS/GreenSpring era are still available for legacy real-time systems. Acces provides free drivers and the AIOWDM/AIOUSB universal library for all their PCI products under Windows and Linux. Acromag IP modules require separate driver software for whichever IP carrier you are using.

For bench and small ATE fixtures, 24–48 channels covers most applications. Large ATE stations for avionics or missile systems often use 128 or more channels across multiple boards. In our current stock: 24-channel (IP-UNIDIG-I), 32-channel (VMIVME-1181), 48-channel (IP-TTL48-8, cPCI-7248), 64-channel (VMIVME-1111, VMIVME-1150), 72-channel (PCI-DIO-72), 120-channel (PCI-DIO-120), 128-channel (VMIVME-1128, VMIVME-2528). For channel counts above 128, stack multiple boards.