Relay Boards With I/O
Computer controlled relay boards, with additional input/output ports.
Relay boards with relays outputs in SPST, SPDT contact configurations, and additional logic level input/output ports to read a logic signal or output a logic level.
Some versions also have opto-isolated inputs on the boards that can handle higher voltage typically up to 28VDC (or more with external components)
8 Channel relay boards have the capability to daisy chain units in a string connected to one control method (RS-232, USB, etc.) on the PC or embedded controller. The first unit connected to the PC can be any of the control methods, and the units connected to the daisy chain are RS-232 units, as shown below. The RS-232 units may be 50 feet minimum between units.
Most 1 & 2 channel units are typically connected to only one control method, however one (1 or 2) channel RS-232 board may be the last board on the daisy chain if only a couple extra relays are needed to save cost. This board would be address "A" as this is set in firmware, and the other boards would need to be set to "B" through "P", so each board may be accessed separately.
- Industrial control applications
- Automatic test equipment (ATE)
- Process control systems
- Power switching applications