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MiniPlex-42USB
The MiniPlex-42USB is the ideal solution for computers and laptops without a
serial port. The functionality of this NMEA multiplexer
is the same as the MiniPlex-42. It features 4 galvanically isolated NMEA inputs,
2 NMEA outputs and one bi-directional USB interface.The two NMEA
outputs (talker ports) allow distribution of the NMEA data to up to eight
instruments.
The MiniPlex-42USB can be connected directly to the USB port of the
computer, without an additional Serial <-> USB converter. The supplied driver
creates a virtual COM port on the computer, allowing all existing navigation
software to be used with this multiplexer.
The combination of the MiniPlex-42USB and it's virtual COM port driver
is a dedicated NMEA solution, as opposed to a generic Serial <-> USB converter.
It therefore does not exhibit the well known problems of these generic
converters like false detection of mice when the GPS is switched on or sudden
drop-outs in the NMEA data stream.
Any attempt of Windows to detect Plug & Play devices on our virtual COM port is
blocked. The result is that the MiniPlex-42USB is a real trouble-free Plug &
Play solution. Just plug in the USB cable, load the driver disk, a few clicks
and you're up and running!
Features
The MiniPlex-42USB has a rich set of features and configuration options,
enabling the user to tackle almost any NMEA bottleneck or interface problem. The
supplied Windows utility MPX-Config allows full configuration of the multiplexer
and monitoring of NMEA data passing through the multiplexer.
| Seatalk® conversion
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When the Seatalk -> NMEA option is selected, NMEA In 4 becomes a
SeaTalk® compatible input, offering conversion of the most
common SeaTalk datagrams on a Raymarine® network into NMEA
sentences. |
| Operating modes
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Server: Data received on the NMEA inputs is sent to the
computer. Data received from the computer is sent to a NMEA output.
Hub: All received data (on the NMEA inputs and from the
computer) is sent to the NMEA output.
Auto: Automatic selection between Server and Hub
mode. This is a useful feature for people who have a GPS and an
autopilot connected to the multiplexer, and sometimes wish to sail
without taking their laptop on board. When the laptop is not connected,
the multiplexer is in Hub mode and crosstrack - and waypoint
information from the GPS is directly sent to the autopilot. When the
laptop is connected and sending data, the multiplexer automatically
switches to Server mode and the autopilot will receive crosstrack
- and waypoint data from the laptop instead.
The Auto mode also serves as an emergency backup: when the
laptop or computer crashes, the multiplexer will fall back to Hub
mode after a time-out of 10 seconds.
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| NMEA Filter
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A flexible NMEA filter can be configured to pass or block specific
sentences from each input channel. This greatly reduces the chance of an
overflow and the resulting loss of data. Many GPS receivers for
instance, transmit RMC, GSV, GSA, GLL and GGA sentences every second,
accounting for 85% of the available bandwidth of the NMEA channel. By
blocking unwanted or unnecessary sentences, bandwidth is preserved for
other instruments. |
| Real-Time
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Gyro- and fluxgate compasses produce NMEA sentences at a high rate
(10 sentences/second or more). This can lead to a buffer overflow in the
multiplexer. Although this overflow is handled properly without data
corruption, it will lead to a delay of NMEA sentences of up to 20
seconds in extreme situations. This produces a severe problem for
autopilots, which cannot make proper course corrections when their
heading feedback is delayed for 20 seconds. The Real-Time option
prevents this delay by bypassing the buffer of that specific channel and
forwarding the data immediately to the multiplexers' NMEA output. As a
result, the heading is never delayed more than 0.2 to 0.5 seconds,
depending on the amount of other NMEA sentences passing through the
multiplexer. |
| Heading conversion
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This option converts a Magnetic Heading sentence (HDG) into a True
Heading sentence (HDT). If the originating magnetic heading sentence
contains a magnetic variation, it is used to calculate the true heading
before conversion. This feature is useful for certain equipment like
VDR's which need a true heading input, while the only available heading
source is a fluxgate, delivering a magnetic heading.
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| Channel Priority
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With Channel Priority enabled, similar NMEA sentences on different
inputs are only passed from the input with the highest priority. The
RS-232 port has the highest priority, followed by inputs 1 to 4, in
descending order. When for instance two GPS receivers are connected to
inputs 1 and 2, and both transmit the same type of NMEA sentences, only
those received on input 1 are passed. A time-out function ensures that
similar sentences from the GPS at input 2 are passed when the GPS at
input 1 stops sending these sentences.
Another example is where a GPS provides an SOG to a windmeter, while the
latter repeats the sentences from the GPS. When the GPS is connected to
input 1 of the muliplexer (high priority) and the windmeter to input 2
(lower priority), the GPS sentences coming from windmeter will be
blocked automatically while wind related sentences are passed. |
| Channel Number
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When this feature is switched on, the multiplexer will transmit a
proprietary NMEA sentence indicating on which input channel the
following NMEA sentence is received.
VirtualPlex-1 uses this to route NMEA sentences from specific inputs to
specific virtual COM ports (Channels option). |
| Channel ID
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The Channel ID option changes the talker ID of every incoming NMEA
sentence in "Mx" where 'x' is a number from 1 to 4, according to the
input the sentence was received on. Example: an incoming GPRMC sentence
on input 2 is changed in M2RMC. This is useful to distinguish between
sentences from two similar instruments. |
| Talker ID substitution
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Talker ID substitution changes the talker ID of incoming sentences
in a similar way as the Channel ID option does, but now the talker ID
can be specified for each input channel. This option is useful for
software or instruments that expect a specific talker ID. |
Screenshot of MPX-Config.
Click to enlarge.
| Specifications: |
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| Supply voltage:
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5VDC from the USB bus or 8-30VDC external
power.
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| Current consumption:
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50mA (100mA max. with fully loaded talker ports)
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| Inputs:
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4 x NMEA-183/RS-422, galvanically isolated
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| Outputs:
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1 x USB, 2 x NMEA-183/RS-422
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| Buffers:
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5 buffers of 1000 characters (4 x NMEA, 1 x USB)
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| Filter list size:
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50 sentence types
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| Priority list size:
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50 sentence types
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| Speed NMEA in:
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4800 Baud
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| Speed NMEA out:
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4800, 9600, 19200 or 38400 Baud
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| Dimensions:
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138 x 62 x 30mm
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A manual
can be downloaded.
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