USB OPTO RLY88 Specifications

usb-opto-rly88-a Interfaces I/O

USB OPTO RLY88 Specifications


The USB-OPTO-RLY88 provides eight optically isolated inputs and eight volt free contact relay outputs with a current rating of up to 1Amp each. It is powered from any standard USB bus and has an exceptionally low maximum current consumption of approx. 90mA with all relays on. The relays are SPCO (Single Pole Change Over) types. The normally open, normally closed and common pins are all available on the screw terminals.



USB – Standard type B receptacle.

Inputs – Absolute Max. 30v DC, Operational 4.5v to 27v DC.

Outputs – Relay Contacts, see power graph below.

LED Indication


Each of the eight input channels has a Green LED to indicate the input status.
Each relay output has a Red LED to indicate the relay status.
Also power status is indicated with an LED driven from the USB supply.

Relay power rating


If the contact load voltage and current of the relay are in the region enclosed by the solid and dotted lines in the figure below, the relay can perform stable switching operation. If the relay is used at a voltage or current exceeding this region, the life of the contacts may be significantly shortened.

plc programming software

First Step – Get The Drivers


Before connecting the USB-OPTO-RLY88 module, you should download the driver and unzip it to a temporary folder. Now connect the USB-OPTO-RLY88 module and navigate windows to the temporary folder and install the driver. The USB-OPTO-RLY88 will now appear as a COM port.

Which COM port?


After installing the drivers, and plugging in the USB-OPTO-RLY88 module to a spare USB port, you will want to know which COM port it has been assigned to. This will vary from system to system depending on how many COM ports you currently have installed. To find out where it is, right click on your «My Computer» desktop icon and select «Properties->Hardware->Device Manager». Now scroll down and open the «Ports (COM & LPT)» tab. You should see the USB serial port listed – COM5 in the example below. If you want to change the COM port number – just right click on it, select properties, select advanced and select the COM port number from the available list. The COM port default will probably be set up for 9600 baud, 8 data bits, no parity and one stop bits, but what ever it is just ignore it. These settings are not actually used because we have a full 12Mbits USB connection right into the heart of the processor.

Using USB OPTO RLY88 with EasyPLC


Due the general character of this card, you can interface any kind of electronic device with your PC and manage it with EasyPLC. The requirements for the input devices are the card input specifications: Absolute Max. 30v DC, Operational 4.5v to 27v DC.
For the Outputs only the relays contacts are activated, the you can interface it with the devices you want to power, taking account for the relays specifications.
Using this card you can create an automatic control system, reading sensors, switches, … and activating lamps, leds, relays, motors, etcc according your EasyPLC Program.

plc programming software

Using USB OPTO RLY88 with Machines Simulator


You can connect your PLC directly with your PC using this card, due the inputs are optoisolators with no common 0Vdc or +Vcc you can create your particular connection depending if your PLC have Source or Sink outputs type. The same for the Inputs (the Relays are independently connected)

Machines Simulator can read directly the PLC outputs (sending the logic states to the virtual machine) and activate the PLC inputs (using the relays) in order the PLC read the virtual machine outputs. With this schema you have a very complete simulation tool to check your PLC programs.


rly88_plc Interfaces I/O