DMX512 ISOLATED SPLITTER/AMPLIFIER OWNERS MANUAL Doug Fleenor Design 396 Corbett Canyon Road Arroyo Grande, CA 93420 (805) 481-9599 revision 1.
PRODUCT DESCRIPTION The Splitter/Amplifier provides between one and eleven DMX512 outputs from a single DMX512 input. The outputs are electrically isolated from the input and from each other by 2500 volt optical couplers. All models of our Splitter/Amplifier boost the signal as well as isolate it. Input levels as low as 0.2 volts are transmitted at full EIA-485 levels (about 4.5 volts).
OPERATION The DMX512 splitter 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 processed by the receive circuit, isolated by the optical couplers, and retransmitted by the driver circuits. All this takes less than 1/10,000,000 of a second. When no DMX input is present, the outputs are placed in an idle condition.
TECHNICAL DETAILS DMX512 uses a "differential" digital signal. A differential signal is a pair of signals which are inverse from one another. That is, when one is high, the other is low. Differential signals are common in both analog processing (balanced microphone cables) and digital processing (digital communications such as EIA-485). Differential signals are used to reduce the effect of electrical noise on long cable runs.
TROUBLESHOOTING We hope your DMX512 Isolated Splitter/Amplifier never needs service. If it does, the information presented here may be of assistance. Access to the inside of the unit is accomplished by removing the top cover. The input fuse is a 1/2 amp 3AG fast blow fuse. The output drivers are 75176B devices. A 75176A will work but is not as rugged. The input receiver is a 75179B. The optical isolator is a 6N137. Schematics are available from Doug Fleenor Design.
