XTB-IIR X10 Transmit Booster
JV Digital
Engineering jvde@att.net
11-27-07
The XTB-IIR is an enhanced Repeater version of the
XTB-II that combines the high-power XTB transmitter with two coupling networks
to drive both 120V legs directly. An
additional passive coupler is not necessary.
The XTB-IIR is designed for split-phase 240V systems. Like the XTB-II, its PIC microcontroller
normally blanks the superfluous X10 bursts produced for 3-phase systems. That allows it to concentrate all its energy
into the X10 burst at the zero crossing, and it can generate a slightly
stronger signal than the XTB. Depending
on line characteristics, the XTB-IIR can output over 20Vpp at 120KHz onto the
AC line.
The
XTB-IIR has a X10 input receptacle that functions similar to the one on the
XTB. A control module such as the CM15A
can be plugged directly into that receptacle, and the XTB-IIR will drive its
boosted output onto both phases. It is
recommended that no more than three X10 transmitters be plugged into that
receptacle. The larger size of the
XTB-IIR allowed room for larger inductors, and the X10 receptacle on the
XTB-IIR can deliver up to 50 watts. An
internal fuse will blow if that rating is exceeded by a significant amount.
The XTB-IIR includes built-in TW523 emulation. A digital I/O line can be run from an
automation controller directly to the XTB-IIR.
The opto-isolated digital interface on the XTB-IIR is functionally
identical to that of the TW523. The
XTB-IIR TW523 emulation differs from the actual TW523 in several regards. The XTB-IIR error checks all incoming data,
and does not produce any output when a collision is detected. The XTB-IIR does not need a gap to separate
X10 messages, and it will recognize each pair of bright/dim commands. The XTB-IIR also includes the ability to
transmit and receive extended messages, but it will not repeat them due to the
overlap issue.
The
XTB-IIR return signal amplifier has been significantly enhanced from that of
the XTB-II. However, line transients
can still make it through the bandpass filter, and are amplified. Devices that are sensitive to noise, such as
the SignalLinc 1132, may not work well when plugged into XTB-IIR.
The
XTB-IIR does not simply plug into a standard receptacle like the XTB. It should be installed adjacent to the
electrical distribution panel where it can drive both phases directly.
Connections to the distribution panel are made through one of the two internal
terminal strips. The other terminal
strip is normally connected to the X10 Input receptacle on the cover. The XTB-IIR should normally be wired to both
phases and neutral through a 240V plug & receptacle fed from a double-pole
15A or 20A circuit breaker. A standard
power cord can be wired to Phase I and Neutral for single-phase operation. Ground is not used internally, and is only
required if the cover contains a grounded receptacle. A solid connection to neutral is essential to prevent damage.
While a
standard 240V 3-prong plug & receptacle are adequate to connect the
standard unit, I recommend 4-conductor power cord wired through a 14-20P plug
& 14-20R receptacle for the grounded unit.
The locking strain relief on the XTB-IIR will accept up to .4-inch
diameter wire. It may be easier to wire
the terminal strip with the board removed from the case. #18 gauge wire is sufficient because the
XTB-IIR is internally fused at 2 amps maximum.
Check the electrical connections carefully before applying power. It is recommended that the terminal strip
screws be re-torqued (with power switched off) to insure solid connections.
The XTB-IIR can act as the powerline interface for
high-end controllers, boost X10 commands received via the X10 Input receptacle,
and repeat X10 commands received over the powerline. No mode changes are required.
The XTB-IIR also includes a smart bright/dim repeater mode, which is
enabled by default. In this mode it
will transmit all but the first bright or dim command received in a sequence. Should there be excessive X10 activity on
the powerline, the XTB-IIR will inhibit its transmitter until the problem is
corrected. Please refer to the XTB-II
Mode Options document for more information on how best to configure the unit
for your particular installation.
The X10
transmitter in the XTB-IIR auto tunes itself to 120KHz using the powerline as a
reference. By default, it only transmits the X10 burst following a zero
crossing. Within that window, the duration of the burst is controlled by the
digital input. If three-phase
transmission is enabled, the transmitted power is reduced, and all bursts will
be transmitted in the standard 3-phase windows.