Basic Guide to Generic Lens Connections
My Pelco equipment has three wires for lens con- nections but the brand X lens my dealer sold me has four! What do I do?
We’ve all heard this problem many times, but it’s really simple to fix once you understand how lens wiring works. All lens motors are DC powered with two wires each, so reversing the polarity on those two motor wires will reverse the direction of the lens movement. If you connect one wire to positive and the other to negative the zoom (or focus) will move in one direction; reverse the wires and it will move the other direction. Typically the wires will be clearly identified as to which pair is zoom and which is focus, but zoom in versus zoom out or focus near versus focus far often gets lost in the translation.
A common description in a lens manual would say something like Yellow-Zoom in +. This tells us that when the yellow wire is positive and the other wire in that pair is negative the lens will zoom in. If the instructions are too vague to figure out the next best thing is to use a nine volt radio battery and figure it out for yourself. Don’t worry, the battery doesn’t have enough power to hurt anything if you get it wrong.
Once you’ve identified the wires the rest is easy. On many lenses, including Pelco’s, one of the two wires on each of the motors is tied to a œcommon point inside the lens to reduce the number of wires the installer has to pull. On most lenses these are the zoom wide (or out), the focus far and on non auto-iris lenses, the iris close. These are the wires you connect together to go to our lens common if your lens doesn’t already do it internally.
Then you connect the zoom tele (or in) to our zoom, the focus near to our focus and the iris open to our iris. A good way to remember which wires go where is to look at any Pelco lens controller. The functions on the bottom row of buttons (or down position on the switches) are the ones that connect to common. Please refer to the diagram below for more information.
That’s all you have to do except call your dealer and tell him next time you want Pelco zoom lenses on your order. Pelco zoom lenses have the proper connectors for plug and play installation. In addition, Pelco lenses are very competitively priced and carry the only 2-year lens warranty in the industry.
NOTE: If your lens has one wiring harness for zoom and focus and a separate harness for iris, it is an autoiris lens. On all auto-iris lenses, the iris connections must be made to the camera only. The harness for the zoom and focus is then connected to Pelco equipment as shown.
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