Rane SR 4 - Manual (Page 10)

Manual-10
SR 4 Wiring Guidelines
Restrictions
24 AWG CAT 5 cable resistance = 26 ohms per 1,000 feet. There are two wir-
ing restrictions. First, RW 485 has a maximum of 1,000 feet. The total length
may not exceed this limit in any combination of series or parallel runs.
Second, the voltage of the power supply also affects the maximum
distance of each length between, and the number of Remotes. Refer to the
tables on the following pages depending on which wire, voltage, number of
Remotes, and if you are using single or multiple runs.
External Power Supply
The RPM 88’s RW 485 port does not offer enough current to power more
than six SR 4 remotes — an external DC supply must be used. Rane recom-
mends using a 12 to 15 volt DC regulated power supply capable of delivering
a minimum of 1 amp of current. The combined current draw on the RPM
88’s RW 485 port and VOP cannot exceed 375 milliamps. [The RPM 44 and
RPM 22, however, can power up to eight SR 4 remotes.]
Most installations will have a mix of SR 2, SR 3, and SR 4 remotes each
with their own current requirements. To make calculation easy as to whether
or not an external supply is necessary, a Microsoft Excel™ spreadsheet is
available named SRXCABLELENGTH.XLS. This file is on the Drag Net
CD-ROM, or downloadable from www.rane.com/smart.html.
If you have a Radio Shack nearby, they offer a 15 volt 1 amp supply, cata-
log number: 273-1691. To ease installation, use a 6 foot Adaptaplug extension
cable, Radio Shack catalog number 273-1641.