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We've launched our new site at www.openlighting.org. This wiki will remain and be updated with more technical information.
Difference between revisions of "DMX512-A"
From wiki.openlighting.org
m (Dmx signals moved to DMX Signals: Corrected the case of the lettets) |
m (added links and a explanation) |
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| + | ''This information is not complete (but may become in a few months)'' The purpose is to introduce the protocol and the details of a packet and maybe explain the required timing of the signal. --[[User:Beier|Beier]] 06:21, 28 January 2007 (PST) | ||
| + | ==Overview== | ||
A ''Universe'' contains 512 addresses and a single DMX line (cable) can only transmit one universe. I.e. a controller with two universes need two DMX lines (daisy chains including splitters). A uniververse is normally thought of as an address space (in the controller), the cables that transmits it and the equipment that receives it. | A ''Universe'' contains 512 addresses and a single DMX line (cable) can only transmit one universe. I.e. a controller with two universes need two DMX lines (daisy chains including splitters). A uniververse is normally thought of as an address space (in the controller), the cables that transmits it and the equipment that receives it. | ||
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* It is up to the controller/transmitter to decide how many addresses that should receive a value. Fever addresses means faster cycles. | * It is up to the controller/transmitter to decide how many addresses that should receive a value. Fever addresses means faster cycles. | ||
| − | + | ==The Packet== | |
| + | * Break | ||
| + | * Mark After Break (MAB) | ||
| + | * A frame contains the value for one address | ||
| + | * start bit | ||
| + | * Stop bits | ||
| + | |||
| + | |||
| + | Sources and additional reading:<br> | ||
| + | [http://www.epanorama.net/links/lights.html#dmx512 ePanorama]<br> | ||
| + | [http://en.wikipedia.org/wiki/DMX_(lighting) Wikipedia]<br> | ||
| + | [http://www.usitt.org/standards/DMX512.html USITT ] | ||
Revision as of 06:21, 28 January 2007
This information is not complete (but may become in a few months) The purpose is to introduce the protocol and the details of a packet and maybe explain the required timing of the signal. --Beier 06:21, 28 January 2007 (PST)
Overview
A Universe contains 512 addresses and a single DMX line (cable) can only transmit one universe. I.e. a controller with two universes need two DMX lines (daisy chains including splitters). A uniververse is normally thought of as an address space (in the controller), the cables that transmits it and the equipment that receives it.
- The DMX signal is made up of a sequence which is sent over and over again (to increase robustness).
- The content is a "start byte" and 512 values, one value for every address.
- The address number is not sent over the lines, so the receiver must count the values from the start of the sequence to find the wanted value.
- A receiver must be set or programmed to an address it listens to. If a receiver listens to multiple addresses, the set one is the first.
- Multiple receiver can listen to the same address - the DMX system does not care.
- It is up to the controller/transmitter to decide how many addresses that should receive a value. Fever addresses means faster cycles.
The Packet
- Break
- Mark After Break (MAB)
- A frame contains the value for one address
- start bit
- Stop bits
