dmx_basics:dmx_in_practice
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| dmx_basics:dmx_in_practice [2013/03/12 22:03] – external edit 127.0.0.1 | dmx_basics:dmx_in_practice [2015/05/27 17:19] (current) – russwig | ||
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| If a fixture like above starts on address 20 and uses 12 addresses then the next fixture address must be at address 32 to avoid overlapping.\\ | If a fixture like above starts on address 20 and uses 12 addresses then the next fixture address must be at address 32 to avoid overlapping.\\ | ||
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| - | The maximum no of fixtures in a chain are 32 and his is due to load on the driver circuit.\\ | + | The maximum no of fixtures in a chain are 32 and this is due to load on the driver circuit.\\ |
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| The last fixture in the chain has to be terminated with a DMX end or terminator.\\ | The last fixture in the chain has to be terminated with a DMX end or terminator.\\ | ||
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| **Why DMX end / termination**\\ | **Why DMX end / termination**\\ | ||
| The DMX termination is a 120 ohm resistor.\\ | The DMX termination is a 120 ohm resistor.\\ | ||
| - | DMX cable has a characteristic impedance of 120 Ohms. It is a bit complex to be described here but it is a complex high frequency calculation of inductors, capacitors, serial | + | DMX cable has a characteristic impedance of 120 Ohms. It is a bit complex to be described here but it is a complex high frequency calculation of induction, capacitance, serial |
| The impedance 120 ohm can not be measured with a multimeter.\\ | The impedance 120 ohm can not be measured with a multimeter.\\ | ||
| - | It is important to terminate the cable with 120 ohm to avoid reflection | + | It is important to terminate the cable with 120 ohm to avoid reflection |
| - | The reflected signal may course | + | The reflected signal may cause the fixture to malfunction.\\ |
| See eventually: [[dmx_basics: | See eventually: [[dmx_basics: | ||
| - | Some fixtures | + | Some fixtures |
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| To build a DMX terminator/ | To build a DMX terminator/ | ||
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| - | Additional | + | Additionally, |
| - | Microphone cable can be used but for longer distance | + | Microphone cable can be used but for longer distance may course the fixtures |
| - | The reason is that audio cables has a higher | + | The reason is that audio cables has a higher |
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| - | This reflection issue is also the reason for not to split the DMX signal with a Y cable.\\ | + | This reflection issue is also the reason for not splitting |
| - | Keep it in one line and if the signal | + | Keep it in one line and if the signal |
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| **Why Splitter**\\ | **Why Splitter**\\ | ||
| Splitting the signal is the same problem as above.\\ | Splitting the signal is the same problem as above.\\ | ||
| - | The load impedance don’t match 120 ohm and this course | + | The load impedance don’t match 120 ohm and this causes possible |
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| The benefit of using a splitter that has building line drivers are that it is possible to have 32 fixtures on all the divided outputs.\\ | The benefit of using a splitter that has building line drivers are that it is possible to have 32 fixtures on all the divided outputs.\\ | ||
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| Finally if it is a optical/ | Finally if it is a optical/ | ||
| - | This eliminate | + | This eliminates |
| The controller is also protected this way.\\ | The controller is also protected this way.\\ | ||
| \\ | \\ | ||
dmx_basics/dmx_in_practice.txt · Last modified: by russwig