Square pegs mounted in round holes

Mounting square displays, controllers and PLCs onto a panel usually requires first cutting a square Hole.

Problem: The aperture is liable to have to be of any size, so the chance of a standard screw up cutting punch happening to have exactly the right dimensions is zero. Square holes normally have to start out as round holes, followed by cutting, and/or sawing and filing to produce the right shape. The pristine flatness of the panel is often spoilt by such processes, although it can usually be bent back into something like the right shape. Solution: Moeller Electric's MFD-Titan intelligent relay requires only two 22.5mm holes to be punched in the panel or enclosure door. The use of two holes rather than one prevents the possibility of rotation and ensures that the IP rating is maintained. The logic module and I/O unit clip onto the rear of the display unit. In its minimum configuration, the unit has 12 inputs and 4 outputs, By using a short DIN rail, it is also possible to attach expansion units or communication modules, such as Profibus DP. The units come supplied as standard with the company's proprietary EasyNet communication facility, a variation of CANbus. The display is 60 x 30mm LCD in an IP65 housing which may be configured to show four lines of 16 characters or a single, four digit numeric. An optional keypad enables control functions to be implemented or set point values to be entered directly into the device. Two LEDs on the front of the unit can also be lit or flashed to attract attention or indicate machine status. Programming is drag and drop using a graphical editor. Once completed, control schemes may be tested off the machine using in-built simulation software. Applications: Small packaging machines, small sampling systems for the water and other industries, small building control systems. Prices start at around £250. TS Moeller Electric