GAL CAN
36 in
MAX RANGE
62 in
DRAWN
TO SCALE
MAX DETECTION ENVELOPE
(10 in x 16 in x 5 in COIL)
52 in
30 in
RMD-1 SENSITIVITY
The sensitivity of the RMD-1 is switch selectable. Normal operation
is in the Hi position. If you are trying to pinpoint a target but the meter
goes to full scale, switch to Low or Med sensitivity. The target is
directly below the center of the coil when the meter is at its highest
point (but not full scale). When operating in Low sensitivity, you can
expect detection ranges about one half of Hi. You can expect these
detection ranges whether the target is buried under mud, coral,
sand, or rocks.
Sensitivity (in water or air): Hi Position
• Piece of eight ......................................................... 10 in.
• Shotgun ................................................................. 28 in.
• 4" diameter pipe .................................................... 34 in.
• One gallon can ...................................................... 36 in.
• 2' x 4' sheet metal .................................................. 50 in.
• Maximum range ..................................................... 62 in.
RMD-1 DETECTION ENVELOPE
The detection envelope for the RMD-1 is very large - much larger
than the coil width/length. The drawing below shows the detection
envelopes (Hi position) for a one gallon can and for the maximum
detection envelope (a very large object).
When using the RMD-1 with a GPS receiver the following connection
and power-up sequence must be followed for proper operation.
1. Cable up entire system including GPS/Loran C to RMD-1,
RMD-1 to the computer (RS232 interface), and RMD-1
downstairs to RMD-1 control box. Also connect all compo-
nents to their proper power sources.
2. Power-up GPS/Loran C and obtain current position fix.
3. Power-up computer.
4. Power-up RMD-1
5. Initiate data collection program on computer.
If the RMD-1 is powered up before the GPS has obtained the current
position or the GPS interface cable is disconnected, the RS232
interface will default to the "No Position Available" message as shown
above.
If the GPS/Loran C loses its position fix during operation, the RMD-
1 will default to the "No Position Available" message".
If either of these conditions occur correct the fault (re-initialize the
GPS, check connections, check battery condition). Once the GPS/
Loran C is again functioning properly, power down the RMD-1, wait
five seconds and power up the RMD-1. The position information
should now be present.
RS232 ON DOWNSTAIRS ELECTRONICS OPTION
With the RS-232 option, the downstairs electronics can be connected
to any computer or data recorder equipped with an RS-232 input. The
specification of the interface is as follows: 8 bit ASCII data, 4800 baud
rate (custom baud rates are available), 1 stop bit and no parity bit.
The message relays the signal strength from the RMD expressed
from 0 to 5,000 millivolt (0 to 5.000 volts). The complete message is
repeated continuously with no delay between messages.
The message sent on the RS-232 output is as follows:
(Note: The message length can vary as shown)
RMD=95mv<cr><lf>
RMD=3270mv<cr><lf>
RMD=5000mv<cr><lf>
•
The baseline reading (no metal present) is approximately 100mv.
See page 9 for connection information.
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