Omron D2EW R5 switch photo

Called the D2EW-R series, their rectangular bodies measure only 8.3 x 5.3 x 7mm (photo right).

“Depending on the voltage across the internal resistors, the system can differentiate between normal switch-open or switch-closed status and an open-circuit or short-circuit at the terminals,” according to the company. “These switches can extend diagnostic monitoring in industrial automation and enhance security protection for equipment such as vending machines and smart meters.”

To allow operation from the side as well as from straight on, the plunger is wedge-shaped and the switch is designed to accept reasonable operating force along its long axis – they are not designed to be side-operated with motion along their short axis.

Omron D2EW R5 switch photoMounting options include polarised posts on the side (above), or M3-screw hole mount with a single post (left).

Terminal options are press-fit, solder terminals (above), straight flying leads (left) or right-angled flying leads (below).

Sealing is to IP67, so they are waterproof.

Operation is over 5 to 18V and -40 to +85°C – but check as some voltage/temperature combinations are not allowed.

Total travel is 2.4mm, and the initial switching position tolerance is ±0.2 or 0.25mm depending on variant.

Omron D2EW R switch diag with resistor circuit web

All parts announced so far have a single normally-open contact, and there is a choice of two resistor arrangement dubbed ‘parallel’ (right-hand in diagram right) right, or ‘series’ (left-hand) – the internal resistors are different in the two cases, and custom versions can be ordered.

Omron D2EW R5 switch photo

Almost all the switches offered are of the parallel type, and measure 3.9kΩ relaxed and 450Ω pushed. The press fit terminal type also comes in a series version, which measures 6.7kΩ relaxed and 1.6kΩ pushed.

Omron’s switches come in two side-exit flying lead options, offering a choice of which end the wires leave

Omron’s D2EW-R series switch web page

Last week, Panasonic aimed some switches at similar applications, that are almost as small, and add a second contact and third lead to improve functional safety.