NorthStar 951X, Installation Manual

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SECTION THREE - Interfacing
951/952 INSTALLATION MANUAL Revision B Page 41
200 ppnm output
The unit provides an open-collector transistor output (on pin 14) that’s
programmed to produce 200 pulses per nautical mile for those devices
requiring this output.
The emitter of the NPN transistor is connected to ground, and the collec-
tor connects to the output pin side (see Figure 21: ”200 PPNM output,”
below). The output can sink 100mA, and can withstand a maximum posi-
tive voltage of 50 volts.
If the output connects to a highly inductive device (for example, a relay),
a spike suppression diode such as a 1N4001 should be connected across
the load. Cathode connects to the power side of the device and anode
connects to the output pin side.
The output produces a negative pulse 80ms wide and supports speeds
from zero to 100 knots (clamps at 100kt).
Figure 21: 200 PPNM output
Configuring the NMEA output ports
Each output port can be programmed to meet most any special require-
ments of devices that conform to the NMEA 0183—and other—data for-
mat specifications. The
function described below allows the
selection of the specific 0183 sentences that the 951/952 will transmit.
1. Press the key until you see the
USER CUSTOMIZATION
screen.
2. Press the menu key to display the
PORT
SETUP OPTIONS
screen.