====== DMX Test Equipment. ======
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Test equipment can be divided in two groups a simple where basics like cable connections and polarity are checked.\\
The other group is a bit more advanced where it is more an analyzer.\\
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The advanced testers can typically the basic tests of cable pin-out.\\
Additional they have signal level and timing analyze eventually with a trigger output for oscilloscope.  \\
But they also monitor channels, record and transmit DMX sequences.\\
Additional some has fixture predefined test pattern like dimmer, pan / tilt curves and so on.\\
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Most error comes from cables that are faulty and a simple cable tester will reveal most errors.\\
It is my opinion that for people that not hardcore each day build-up large rigs with many lights or maintaining many fixtures a simple cable tester will be sufficient.\\
A tester like the picture bellow is relative cheap but very useful.\\
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{{:dmx_basics:dmx_palmer_cable_tester.jpg?direct&800|}}\\
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A simple cable tester can be a DIY project.\\
Here is a suggestion of some circuits that can be handy to have in a tester.\\
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The first suggestion is a simple circuit that makes it possible, via a rotary switch, to see that all wires in the cable are ok and not broken or shorted.\\
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{{:dmx_basics:dmx_cable_tester.gif|}}\\
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Next a circuit that makes it possible to see if there are a DMX signal in the chain.\\
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{{:dmx_basics:dmx_signal_tester.gif|}}\\
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This sniffer circuit is just added so it is possible show the DMX signal here on the Wiki.\\
It is a circuit with two BNC connectors so it is possible to attach an oscilloscope to the lines.\\
Unfortunately is it too difficult to make a circuit that generates a trigger signal for a given DMX channel so this is not included under simple tester.\\
And it can be discussed if a serial resistor are to be added in two sniffer lines so an antenna effect are avoided.\\
See: [[dmx_basics:dmx_measurements|]]\\
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{{:dmx_basics:dmx_oscilloscope_coupler.gif|}}\\
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And bellow is some pictures of how it can be realized.\\
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{{:dmx_basics:dmx_tester_top.jpg?direct&800|}}\\
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{{:dmx_basics:dmx_tester_side_2.jpg?direct&800|}}\\
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{{:dmx_basics:dmx_tester_side_1.jpg?direct&800|}}\\
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{{:dmx_basics:dmx_tester_open.jpg?direct&800|}}\\
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