Manual - Doug Fleenor Design
Contents
1. CONSOLE Presenting the ONE isolator solution DIMMER ISOLATOR DIMMER and the TWO isolator solution ISOLATOR DIMMER ISOLATOR DIMMER LINE TERMINATION Line Termination refers to the electrical properties at the end of a control cable In analog and analog multiplex systems line termination is less important than it is in high speed digital applications Termination always improves DMX512 s Signal quality In some simple cases it can be ignored with little loss of reliability Line Termination becomes more important as cable length increases and as more dimmers receivers are connected to the line In complex systems with dimmers separated by more than a few feet termination is recommended Termination is provided by connecting a resistor between the Data True Data and Data Complement Data lines at the very end of the control cable run to the control out connector of the last dimmer To be technically accurate the value of the resistor should match the characteristic impedance of the wire used for control wiring This characteristic impedance is often not known for the wire being used as control cable A common impedance for RS 485 digital control cable is 120 Ohms Even if the control2. is passive is the Input Pinouts 5 pin male XLR style accepts DMX512 UU BWNHE DMX Opto Isol Data True No Connection Data Complement Data Data No Connection No Connection Lator Output Pinouts 5 pin female XLR style meets OP wWNEFR Common Data True Data Complement Data No Connection No Connection DMX 512 standard Data BREAKING GROUND LOOPS The term Ground Loop refers to an electrical connection that results in two paths for curren t from one point to another with one of the paths usually occurring through the building s electrical ground system Ground 1 electrical equipment being connecte oops result from two pieces of d to electrical power in different places and then being connected together In audio systems ground loops frequently occur and can result in audible hum or buzz The art of eliminating ground loops in audio systems is simplified by being able buzz goes away the job is done Serious ground loops in dimming sys to hear the result when the tems are less common but can be difficult to trouble shoot if they exist Unlike audio loops that result in an audible hum a ground loop in a multiplexed dimmer control application may not symptoms A ground loop in an anal or CD 80 can result in steady flic lo
3. DOUG FLEENOR DESIGN 805 481 9599 DMX512 OPTICAL ISOLATOR OWNERS MANUAL Doug Fleenor Design 396 Corbett Canyon Road Arroyo Grande CA 93420 805 481 9599 revision 2 0 December 1996 PRODUCT DESCRIPTION The electrical Isolator DMX512 Optical isolation between light dimmers when connections is broken by using an op using a beam of control signal instal DMX Opto Isolator led in the control line con against sole from damage in the Isolator may also be used lighting damage line intersections The input stage of the DMX Opto Isolator is passive Institute for Theater Technology DMX512 calls for the input of a receiving device t The DMX Opto Isolator s passive i States for meet The DMX512 high speed optocoupler is to insure that the does not introduce any signal degradation daisy chained specifications adhere to EIA 485 DMX512 specificat more informat DMX512 DMX Opto data rate tion tion on and why it Isolator u is 250 Kilo Baud light event of the and buffer wyes DMX signal USITT s and so it s input does not See the Opto Isolator s input doesn t need to ses a 1 Designed to protect dimmer failure to eliminate ground loops this manual s section on ins provides complete ting consoles and assoc
4. Isolator works Differential Digital Signals signal cables and EIA 485 electrical DMX512 uses a differential l is a pair of signals which are inverse from one another That is when one is high the other is low signals are common in both analog processing digital processing Differential on long cable runs noise is processe 485 receive signal rema Differentia d by ins that it is not noticeable here is a brief description A differential digita L signals are the receiving circuit r for exampl le the noise which they up is of eq equal magni of or or signals hot ee A retu O In DMX512 differen rn tial Erue or E a third line signals signal all together and uses only differentia signa data line t drives the signals al travel are usually ual magnitude on bot tude on each wire so that effectively subtract the noise and leave are usually denoted by a plus line and by a min complement When line common is The DMX Opto the da ways travel in pairs twisted to th wires the relative state the data line is higher he LED indicator is il data line high lluminated and the o signal Differential balanced microphone digital communications such as used to reduce th ffect of When a differential signa
5. R reflections but re transml ted the In fact DMX rate SO signal to the middle dimmers It s not just because we make the isolator that we present next solution but we don t mind selling all those isolators either CONSOLE ISOLATOR ISOLATOR DIM ISOLATOR In some cases this may be overkill but it can t hurt the need to daisy chain isolators is the main reason the Optical Isolator is 40 times faster than the DMX512 data that daisy chaining will not degrade the signal quality just look at all the protect storm damage And tion you get from dimmer failure and Sometimes it is necessary for a control run to be split before reaching the first dimmer The resulting wye connection is a reflection nightmare Now you have reflections coming directions from two and you can t even terminate both ends of without overloading the console CONSOLE DIMMER DIMMER the wye Editors Note The proper item to use in this situation is an isolated splitter Doug Fleenor Design now makes spli three five CONSOLE tters with and eleven outputs These diagrams have been left in the manual for emergency use when no splitters ar e on hand
6. back up the line Two possible solutions exist to this problem eliminate the reflections see the section on line termination or isolate the reflections from the dimmers in the middle of the control run by placing a DMX Opt ical connection of the dimmer in Since cannot go reaching CONSOLE The f DMX Optical control line more ahead of the isola the dimmers and the isol placing the isolator afi licker or blink the isolator is a it s input and re transmitting it on it s output the isolator and distort the signal backwards through the middle dimmer one way the loop devic IMMER through Isolating the middle dimmers from reflections may be accomplished Tsolator at the middle of the control line receiving a signal the reflection on ISOLATOR than a dimmer TO middle dimmers CONSOLE r If the console may not be able to Lator too Although no ter the dimmers causes try placing the isolator just ISOLATOR IMMERS IMMER Isolator has a passive input which loads there are lots of dimmers drive all likely the If ahead of the dimmers to the This configuration does not suppresses them by supplying a very strong isolat th IMME
7. cable used is not exactly 120 Ohms terminating the control line with a 120 Ohm resistor is better than leaving it unterminated at 22 000 Ohms A simple terminator may be made by soldering a 120 Ohm 1 4 Watt resistor between pins 2 and 3 of a 5 pin XLR style connector and plugging it into the last dimmer in the chain It is suggested that the connector be wrapped with white electrical tape and labeled DMX LINE TERMINATOR for easy identification If you don t like soldering a professionally constructed terminator is available from Doug Fleenor Design Editor s Note Since this manual was first written in 1990 DMX512 systems have become more and more elaborate Doug Fleenor Design now recommends termination of all DMX512 systems regardless of complexity Terminators cost less than 25 00 Why risk failure Typical Characteristic Impedances of Control Wire BELDEN SERIES NUMBER NOMINAL IMPEDANCE 9804 100 Ohms 8132 120 Ohms 9829 100 Ohms 8332 Not Rated 9501 Not Rated 8102 100 Ohms 9729 100 Ohms 8162 100 Ohms 9990 50 Ohms 9841 120 Ohms 9880 100 Ohms 8777 50 Ohms 9873 50 Ohms 9773 50 Ohms ETA 485 drivers on which DMX512 is based are rated fora minimum load impedance of 60 Ohms Use of cables with a characteristic impedance of less than 100 Ohms is not recommended If such cable
8. iated The electrical tocoupler which passes the the Op prote cont at The o meet E nput doe strictly meet the to Gt rol United tandard for TA 485 s not the tal why it 0 000 Kilo Baud optocoupler The reason for using such a DMX Opto Isolator ven when several are Loge ther lation doesn t The The DMX Opto Isolator s output section is fully DMX512 and EIA 485 compatible Baud operation The output SETUP AND CONNECTIONS The DMX Opto console as possible isolator directly into the output control cable onto the end of the Isolator is designed to be placed as In fact it jack of the cons isolator close to is possible to plug the ole and cables connection eliminates the need for any additional In some installations the isolator likelihood of damage to installation unwise In 2 cable may b the isolator may be placed on The isolator does not need for proper operation console and the isolator allow DMX51 that console the console is too close hang off the back the these cases TO extended connector a short 1 used between the console and However the longer the cabl the less tic induction provide from electro magn The DMX512 input to connector the connectors specified in co
9. l microphone pre amp or RS can be eliminated but the and the wire on insure any noise picked The noise must be of receiving circuit can the signal The pairs sign on the normal sign on the inverted the US to the the common of the than the utput driver run in addition Isolator ignores ta line low When the data line is lower than the data line the LED indicator is extinguished and the output driver drives the data line low the data line high When there is no drive to the isolator such as when the console is turned off the LED indicator is extinguished and the output driver drives the data lines to their idle state data line high data line low ABOUT THE COMPANY Doug Fleenor Design is a semi custom design and manufacturing company Our current standard products include converters for many lighting control protocols Optical Isolation products for DMX512 AMX192 and other digital protocols and a Digital Multiplex Combine Unit for combining two Digital Multiplex Signals in a pile on route or patch operation All these standard products can be customized for particular needs Doug Fleenor Principle Engineer has been designing for the entertainment industry since 1979 He spent the years from 1984 through 1990 as Teatronics Chief Engineer During this time his work on advancing mul
10. nnector connector connector connector the isolator is a male 5 pin the as or the uch as f S f S input the Switchcraft output from the isolator is a male 5 pin the Switchcraft output is a female 5 pin connector The mating the DMX512 standard to the isolator is a femal model A5F model A5M 1 driver is also capable of 10 000 Kilo the the This method of to the wall to In other cases the makes the direct to 2 meter the isolator so the floor or table near the to be close to the console betw protection the isolator will XLR sty Thes n th le th e 5 pin The mating ar The input designed whereas port to the DMX Opto Isolat DMX512 standard specifies an act Tsolator s input does not meet not a serious drawback however load on a part ly several to be specificat the port ano console tion the only there are usuall The isolator s output mee and restores lator s input however The fact that the isol that it be placed close to the ther reason it is recommended DMX Opto Isolator CS tor is passive tive input DMX512 specification since the Opto Isolator is and since the DMX Opto the This is ticular console port dimmers connected to one the full DMX512 the full drive capability of
11. o PROTECTING AGAINST ELECTRICAL STORM DAMAGE Voltages ind may be isol circuitry by cable of the isol a uced on ted from placing Shielded cable sho both a Cor at uld the console then to long control cables during electrical the console and an Opto Isola the dimmer input to connect the of the dimmer with the shield connected to pin 1 at the conso and to a good eart th ground at the dimmer end storms tor at each end of the control be used the input output the isolator at le end Extremely high voltages caused by direct strikes to lighting towers or power op of a backup tocoupler or E such failure The isolator removing the console or isolator should b dimmer or console feeds may still ca Isolators install use damage With Optical led this damage will hopefully be limited to the A 485 driver inside the isolator In the event the Optical Isolator may be easily replaced with may then be returned for repair without dimmers from service The repair to the less expensive than repair to an unprotected plus it s easier to ship BUFFERING CONTROL LINE INTERSECTIONS WYES Editors Note only isolation product line of isolation and distribution products more suitable for the problems listed below is left many of which Isolator when more suitable p
12. op in a digi tal multiplex system long periods of time hours or days is an advantage to digital multiple noise and ground loops On the other hand if a problem exists it is harder to pinpoint When hum exists in an audio system ground is an audio transformer Th Signal through a magnetic field whi connection The DMX Optical Isolat for a DMX512 control signal It pa Signal using connection system a DMX insure that no ground loop can be m Make sure however that there is n she of your metal and will isolation circuitry if a connection If you suspect a ground loop is cau have continuous visible og multiplex system AMX 192 ker but even a bad ground may not impair performance for From one standpoint this X it is much more immune to one useful tool to isolate e transformer passes the audio a beam of light whil Optical Isolator ins control wiring connec le breaking the electrical or provides a similar function sses the lighting control e breaking the electrical sing problems in your lighting talled at the console will ade through the isolator o connection to the metal tors The isolator s shell is carry current around the isolator s internal connector on y pins 1 2 and 3 sh them is made to the shell of the ould have any connections t
13. roducts are not on hand The data rate of relatively high data rate signal distortion A ref reflections reaches th nd of the wire is reflected back up the wire In a simple system and the dimmer s significant problem reflection is not wire th Signal distortion often does not cause errors Consider what happens where DMX512 is 250 000 bits per second and is susceptible One cause of signal distortion is lection is caused when an electrical a portion of the console is at are at the other end however seen Since the dimmers are at the end of by them if a dimmer is placed in This When this product was introduced in 1990 it was our Doug Fleenor Design now makes a complete are The following text in this manual as a guide on how to use the Optical isa to errors caused by signal one end of the the electrical energy wire reflections may not be a the and the resulting the middle of the wire such as if a run is made from the console to the stage right dimmers and on to the stage left dimmers The stage left dimmers are at the end of the cable and do not see the reflections going back up the wire The stage right dimmers located in the middle of the control run see the initial control signal from the console but it is distorted by the reflected signal coming
14. s are used terminate with a minimum of 60 Ohms If the impedance of the control cable is not known a termination of 120 Ohms is recommended OPERATION The DMX Opto Isolator has no operator controls it is fully automatic It should be left plugged in at all times for automatic operation When a DMX signal is applied to the input it is isolated by the optocoupler and instantly within 1 10 000 000 second retransmitted by the output driver When the signal is removed from the input the optocoupler is idle however the output driver continues idle high state is th For power s into a swit state as long as te as defined by e idle sta avings the ched outlet sequenc The illuminated isolator in ch anged TECHNICAL For those technical types out there required in powering up when a It is not a dicator to change intensit This effect may be so sligh DETAILS Converter may be unplugged when not in isolator has one indicator LED DMX signal is presen indicator ty slightly as dimmer levels are power the isolator is powered drive the DMX line in an The high DMX512 specification to th e or plugged use There is no special the dimmers console isolator dicator is the input of the is normal for the This in on toe of how the DMX Opto
15. tiplex control consoles dimmers and systems earned him the nick name Doctor Mux Doug Fleenor Design continues to provide solutions to multiplex control problems as well as designing custom and semi custom control and dimming systems WARRANTY Products manufactured by Doug Fleenor Design carry a five year warranty If the product breaks due to a manufacturing defect within five years of manufacture Doug Fleenor Design will repair it It is the customer s responsibility to return the product to Doug Fleenor Design at the customer s expense Doug Fleenor Design will repair the unit and return it to the customer at Doug Fleenor Design s expense If a trip is necessary to the customer s site to solve a problem the expenses of the trip must be paid by the customer If your unit is out of warranty please call us anyway We try to be fair on all repairs If the failure was our fault we will usually repair it at no charge regardless of the time period We want you to be happy with your purchase 10
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