Relay Output / Isolated Input Module for PC/104 Bus

RELAYIO-104 RELAYIO-104 Block Diagram

  • Stock Number:

  • 100-7610

  • Budgetary Pricing:

  • $179.00 / 001 - 009
  • $170.05 / 010 - 024
  • $161.10 / 025 - 049
  • $152.15 / 050 - 099
  • $143.20 / 100 - 249
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  • Typical Lead-Time:

  • Stock - 2wks

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The RELAYIO-104 is an 8-bit digital I/O peripheral module offering electrical isolation between the host and externally connected devices. It conforms to the PC/104 standard and operates on a single +5V power supply. A single 40-pin I/O header is used for all external wiring.

Relay Outputs

Eight SPDT (form C) relays are used for the digital outputs. Independent access to each relay's Normally-Closed, Normally-Open and Common terminals eases wiring constraints and permits flexible mixing of AC and DC signals. Each output is capable of controlling loads up to 1A @ 24Vdc or 0.5A @ 125VRMS. They also feature short-preventing break-before-make operation. A single output register controls the on/off state of the eight relays. All relays are de-activated and in their Normally-Closed state during power-off and system reset. A relay is activated by writing a "1" to its corresponding bit within the output register. Writing the same bit as "0" deactivates that relay. The output register is readable and writable, permitting read-modify-write software bit manipulations to be used.

Digital Inputs

Digital Inputs: Eight separate inputs using non-polarized optical isolators are provided, allowing any combination of DC or AC signals to be monitored. Their wide input voltage range, 3-24V, is suitable for a diverse range of applications. Each input has an associated low-pass filter that can be individually enabled for the reliable measurement of AC signals as low as 40hz. The on/off states of the inputs are held in a single read-only register. An activated input appears as a "1" in its corresponding bit position. Digital Input #0 has the added capability of optionally generating a host interrupt the moment it becomes activated. The event is latched in an interrupt status register so that even a short duration input will not go unrecognized. Applications which do not need full interrupt capability can still use this function by simply polling the interrupt status register. The status register is cleared during system reset or by writing any value to it.


  • Eight SPDT (form C) relay outputs
  • Eight optically isolated AC/DC digital inputs
  • Individual input filters for reliable sensing of AC and noisy signals
  • Interrupt feature catches momentary input events
  • 500V isolation between PC/104 bus and I/O signals



I/O Connections:40 Position IDC type header
Isolation:All I/O: 500V DC or AC, input-to-board or board-to-output
Isolation between I/O signals: 100V maximum
Addressing:8-bit PC/104 bus. Occupies any consecutive 4-byte block in host's I/O map, 0x00016 through 0x3fc16
Power Requirement:+5Vdc ±5% @ 80mA typical. Additional 30ma required for each activated relay
Dimensions:PC/104 compliant, 3.55"W x 3.775"L. 8-bit stack-through, optional 16-bit stack-through
Environmental:Operating temperature: -20°C to 70°C
Non-condensing relative humidity: 5% to 95%
Product Origin:Designed, Engineered, and Assembled in U.S.A. by SCIDYNE Corporation using domestic and foreign components.
Relay Outputs
General:Eight SPDT (Form C) sealed electromechanical relays,Break-Before-Make operation
Power Handling:DC: 1 Ampere @ 30Vdc maximum
AC: 0.5 Ampere @ 125VRMS maximum (resistive load)
Switching Capacity:1ma, 5Vdc minimum, 62.50 VA, 30W maximum
Contact Resistance:100mΩ maximum, Ag (Au clad) contacts
Operate Time:5ms maximum (activate or release)
Service Life:5 x 106 operations minimum
Digital Inputs
General:Eight independent non-polarized optically isolated inputs
Input Voltages:DC: 3V minimum, 24V maximum, non-polarized
AC: 3VPP minimum, 24VPP maximum, 40hz to 1khz
Switching Time:Typical @ 5V, Filter Disabled: On: 40μs Off: 100μs
Filter Enabled: On: 20ms Off: 85ms
Input Impedence:1.8kΩ minimum
AC Input Filter:RC type low-pass. Selectable on a per input basis
Interrupt:One interrupt, Jumper selectable IRQ 3,4,5,6,7 9 (10,11,12,14,15)* or Disable. Fully supports sharing. Associated with digital input #0 activation, positive edge sensitive. * Optional 20-Position J2/P2 stack-through connector required for upper IRQs.

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