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External Relay Accessory Board



The Measurement Computing brand CIO-ERB24 from Firetail DAQ is a 24-channel relay accessory for digital I/O and multifunction boards. The CIO-ERB24 is equipped with 24 SPDT FORM C (single pole, double throw) relays. The CIO-ERB24 does not require a separate 240 VAC power supply as it runs from the computer's 5V power supply through a four-pin MOLEX connector or an external 5V supply.

The CIO-ERB24 inputs from the digital I/O board are pulled to a steady state by circuitry on the board, so they do not randomly open or close on power-up. Also, buffer/ drivers on board accept signals from simple 8255 TTL LS type digital I/O boards and provide ample current to operate the relays and provide Back EMF protection to your control board.

The CIO-ERB24 has screw terminals for connecting your field wiring to the relays. Each relay has three terminals: COMMON, NORMALLY OPEN and NORMALLY CLOSED. The screw terminals are high-quality jaw types that do not bind when removing wires. We recommend using 12-22 AWG wire gauge. The screw terminal/module numbers correspond to 8255 ports:

  • 1 to 8 correspond to PORTA bits 0 to 7
  • 9 to 16 correspond to PORTB bits 0 to 7
  • 17 to 20 correspond to PORTC Low bits 0 to 3
  • 21 to 24 correspond to PORTC High bits 4 to 7

The CIO-ERB24 has one 37-pin D type connector and two 50-pin connectors. Use a C50FF-x cable to connect with 48-bit DIO boards, such as the PCI-DIO48. Use a C37FF-x cable to connect with 24-bit DIO boards, such as the PCI-DIO or USB-DIO24/37. If you have a second CIO-ERB24 board you can drive it from the unused digital lines of a 48-bit DIO board by simply connect a C50FF-x cable from the "OUT" connector of the first CIO-ERB24 to the "IN" connector of the second CIO-ERB24.

Supported Products: CIO- PCI-, PCIM- and PCIe- DAS and DIO series boards and USB-DIO modules

External Relay Board (ERB) Comparison Table

Board / Feature Bits / Type To Suit
CIO-ERB08 8 Form C 6A EM Relays CIO- / PCI-/ USB–DIO24 and DAS Boards
CIO-SERB08 8 Form C 10A EM Relays CIO- / PCI–/USB- DIO24 and DAS Boards
CIO-ERB24 24 Form C 6A EM Relays CIO- / PCI–/ USB-DIO24/48 and DAS Boards
CIO-SERB24 24 Form C 10A EM Relays CIO- / PCI–/USB-DIO24/48 and DAS Boards
CIO-SERB24/FD 24 Form C 10A EM Relays Fault detecting CIO- / PCI–/USB- DIO24/48 and DAS Boards
CIO-ERB48 48 Form C 6A EM Relays CIO- / PCI–DIO48
CIO-SERB48 48 Form C 10A EM Relays CIO -/ PCI–DIO48
6K-ERB-08 8 Form C 6A EM Relays PCI-DAS6000 series boards

Contact our team today to find out which Data Acquisition device is the right one for your application.