VX-4026 universal relay switching Eurocards

Programmable Logic Arrays (PALs) provide each relay with its control signal to operate or release. The VX-4026 card is configured so that these signals are derived from logical combinations of the control inputs and status signals from the relays themselves. This flexibility and reliability of control does not use microprocessor or real-time software, and makes system design and rack/control panel cabling very straightforward. It also minimizes the number of relays required to perform quite complex operations, in turn reducing the number of relays through which the signal must pass. Relay status is derived from the drivers themselves, and is brought to the edge connector (as well as to the front-of-board LED status on the eight-relay model VX-4026-1).

Model VX-4026-1 has up to 8 on-board relays with full access to all contacts on all relays, which is useful for changeover switching and alarm monitoring systems. Model VX-4026-2 has two banks of 8 relays, the second bank operating as a slave 1 from 8 selection with separate control, suitable for matrix switching applications where space and cost may be at a premium.

The signal paths themselves are arranged for flexible configuration. By using on-board links, a pair of contacts from each of the relays can be bussed together providing, for instance, source selection and matrix switching applications. Relays may be bussed together in groups of varying sizes, accommodating a video and audio bus on a single card. For larger matrices, several cards can be cascaded.