Relay Output / Isolated Input Module for PC/104 Bus

RELAYIO-104 RELAYIO-104 Block Diagram

  • Stock Number:

  • 100-7610

  • Budgetary Pricing:

  • $188.12 / 001 - 009
  • $180.60/ 010 - 024
  • $173.37 / 025 - 049
  • $166.58 / 50+
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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 40-pin IDC ribbon connector 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 Break-Before-Make operation.

An 8-bit output register controls the state of the eight relays. By default, all relays are in a de-activated ( 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 a bit as "0" de-activates the corresponding relay. The register is both readable and writable facilitating efficient Read-Modify-Write bit manipulations software techniques to be used.

Optically Isolated Digital Inputs

Eight separate inputs using non-polarized optical isolators allow 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. The filter is especially helpful when monitoring noisy DC signals.

The on/off states of the inputs are held in an 8-bit 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 event will not go unrecognized. Applications which do not need full interrupt capability can still use this function by simply polling the interrupt status register.


  • Eight SPDT (form C) relay outputs
  • Eight optically isolated AC/DC digital inputs
  • All inputs and outputs are electrically isolated from each other
  • Individual input filters for reliable sensing of AC and noisy DC signals
  • Interrupt feature catches momentary input events
  • 250V isolation between PC/104 bus and I/O signals



I/O Connections:40 Position IDC type header
Isolation:All I/O: 250V DC or AC, board-to-field. 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%
CA Residents: Warning - Prop 65 Info
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 Impedance: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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