Electromechanical relays have several advantages over solid-state relays. They are usually less expensive; they are more flexible because they require less current sink from the digital I/O board; and they are smaller, so they can be packaged to take up less space. Relays have their drawbacks, however. They can arc or surge when used with devices carrying an inductive load (such as motors), and they don't offer the same optical isolation. Important: When using CYERB for switching inductive loads, use the newer CYDO output only boards, which cannot be reset by the "inductive kick."
The digital I/O lines to the CYERB are pulled to a steady state by circuitry in the board so they do not randomly open or close on power-up.
On-board buffer/drivers allow the CYERB 24 to be controlled by any LSTTL or NMOS/CMOS device. Compensating for the lack of current sink in such low-power devices, it makes an ideal companion for 8255-type devices, such as the auxiliary I/O on the CYDAS 1600. |