TPCMQ DC/DC CONVERTER SERIES
OPERATING MANUAL
11
C O R P O R A T I O N
12.6 Remote Sensing.
Remote sensing connections are made to pins 11
(+Sense) and 23 (-Sense) of the converter rack/shelf J4 connector. Re-
mote sensing is used to regulate the output voltage at the point of load by
compensating for the voltage drop in the wires to the load. The +Sense
lead must be connected to the + side of the load and the -Sense to the
- side of the load. The sense leads should be a color-coded, twisted pair of
AWG no. 22 or 24 copper wire. See Fig. 6.
Remote sensing can compensate for a total voltage drop of 0.5V, or 0.25V
per load wire. The sense leads should not exceed 10 feet (3 meters) in
length. If remote sensing is not required, the sense leads may be left open
for local sensing at the output terminals. Be careful not to reverse the
sense lead connections, as this could damage the output.
12.7 Control and Supervisory Signals.
All control and supervisory signals are
accessible at J4, a 25-pin subminiature D connector at the back of the
converter rack/shelf. See Section 16 for a complete description of these
input and output signals.
12.8 Alarm Signals.
Among the control and supervisory signals are three logic
alarms: Input Power Fail, Output Power Good and Overtemperature Warn-
ing.
They are logic signals referenced to -Sense, J4 Pin 23. There are logic
alarms for each converter module. The fi rst alarm is Input Power Fail. A
logic HI indicates that there is no DC input. The second alarm is Output
Power Good. A logic HI indicates a DC output failure. The third alarm is
Overtemperature Warning. A logic HI indicates the internal air temperature
has reached a critical level just prior to the unit shutting down.
13.0 PARALLEL OPERATION
The converter modules in the rack/shelf are all connected in the parallel, current
sharing mode by means of a single-wire current share connection among them.
A rack/shelf can be operated in either an N+1 redundant mode or non-redundant
mode.
13.1 Redundant
Operation.
From Table 13-1, the 19-inch shelf can be oper-
ated in a 2+1 redundant mode. This means that the full load current must
be carried by two converter modules. While operating normally, the current
is shared approximately equally among the three modules. If one module
fails, however, the output current is then maintained by the two operating
modules. The failed unit can then be replaced without affecting
