HYDROMEA LUMA 100 User manual

LUMA 100
a fast, low-power, optical underwater communication system
Manual
Ver 1.2
4/2021

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Contents
1 Introduction ............................................................................................................................ 3
2 Operation ................................................................................................................................ 3
2.1 Setup ................................................................................................................................ 3
2.2 Operation ......................................................................................................................... 3
3 Modem configuration ............................................................................................................. 4
3.1 Connecting the modem .................................................................................................... 5
3.2 Communication settings .................................................................................................. 6
3.2.1 Serial baud-rate ......................................................................................................... 6
3.2.2 Maximum packet size ............................................................................................... 6
3.2.3 Data wait time ........................................................................................................... 6
3.2.4 Forward error correction .......................................................................................... 6
3.2.5 Packet transmit mode ............................................................................................... 7
3.2.6 Beacon period ........................................................................................................... 7
3.2.7 Auto off delay ............................................................................................................ 7
3.3 Sleep mode configuration example: ................................................................................ 7
3.4 Firmware update .............................................................................................................. 8
4 Maintenance ........................................................................................................................... 8
5 Electrical and Software Characteristics .................................................................................. 9
6 Mechanical Characteristics ................................................................................................... 10
7 Errata ..................................................................................................................................... 12

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1 Introduction
The LUMA 100 is an optical modem for fast, reliable underwater communication. Each LUMA
100 is a full transceiver and thus capable of half-duplex communication (transmission and
reception). A deep-sleep mode which the modem will enter after no data was received or
transmitted for a set amount of time drastically reduces the power consumption. During deep-
sleep the receiver is still active and the modem will wake up within 100 ms after receiving a
beacon message from another modem.
2 Operation
2.1 Setup
Attach both modems to their respective host systems using matching female SubConn Micro 6
connectors such as MCIL6F, MCBH6F, MCOM6F, MCPBOF6F or MCDC6F. Please make sure to
match the pinout provided in Electrical and Software Characteristics.
 Apply a suitable supply voltage (12 V – 36 V).
 When properly aligned and within communication range, the two modems now provide
a half-duplex serial communication link.
2.2 Operation
When in active mode the modem will broadcast all data received over the cable and
send over the cable all data received from the optical receiver. When in sleep mode the
modem ignores all data coming in from the optical receiver and the cable. Only a
specific beacon message or power-cycling can wake up the modem.
Auto-sleep: When enabled, the modem will automatically enter sleep mode if no data
has been sent or received for a set period which can be configured.
Beacon transmission: When the beacon interval time is set to a non-zero value the
modem will regularly send a beacon message at the specified rate. Any modem in sleep
mode which is within range will be woken up by the beacon.
WARNING:
 bright LED light source, do not look directly at emitter
 a few people may experience epileptic seizures when
viewing flashing lights

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Thermal fold-back: The emitter of the modem consists of 12 high-power LEDs
composed of one bank of 6 LEDs and two banks of 3 LEDs each. During normal operation
all 12 LEDs are transmitting in parallel to provide the highest possible transmission
range. If the circuit board temperature rises above 60°C the modem will dynamically
switch off emitter banks until the temperature returns to a safe level.
3 Modem configuration
The LUMA modems can be configured with the LumaConf software, available here (note:
LumaConf for the LUMA 250LP also works with LUMA 100):
https://files.hydromea.com/luma/LumaConf_250LP.zip
The LUMA modems can be configured with the LumaConf software. LumaConf runs on
Windows 7, Windows 8 and Windows 10, 64 bit version. Installation is not required; simply
extract lumaconf.exe from the ZIP archive to a location of your preference (e.g. the
Desktop) and run it. Windows may generate a warning about running software downloaded
from the internet, which can be ignored.

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Figure 1: LumaConf modem configuration software
3.1 Connecting the modem
 Plug the LUMA modem with a serial adapter cable into a serial port, or via a USB-to-
serial converter. Connect a power supply to the cable (12 V – 36 V)
 In the top left corner, set the correct COM port and baud-rate. The default setting is
115200 bps, but it may be different if the modems have been configured to another
baud-rate.
 Click on "Config mode", and the parameters should become active (instead of greyed
out) if all settings and connections are correct.
 The modem is now in configuration mode, which allows you to change the modem
settings. Changed settings will be applied instantly but will revert to the previous
settings after a power cycle. To save the new settings to the modem’s internal flash

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memory, click “Save”. To leave configuration mode and return to regular operation, click
“Active mode”.
3.2 Communication settings
3.2.1 Serial baud-rate
This is the baud-rate setting for the communication to the modem over the attached cable. The
baud-rate has to match the selected baud-rate of the host computer or connected device.
Available baud-rates are:
9600, 19200, 38400, 57600, 115200 bits per second (default 115200 bps)
When changing the baud-rate of the modem, the baud-rate of the host PC also has to be
changed to the same value.
Note that the changed baud-rate is not permanent until a “Save” command is sent, which is
only possible if the new baud-rate settings work on the modem and the host PC.
3.2.2 Maximum packet size
The modem collects serial input data from the RS232/485 connection to combine it into a
packet. This parameter specifies the maximum packet size. Packets can be smaller if there is no
more input data after a specified time period. Large values reduce overhead, small values
improve latency. The default value is 64, which is a good compromise.
3.2.3 Data wait time
This parameter specifies the maximum time in microseconds that the modem will wait for
additional data before sending a packet before the maximum packet size is reached. Larger
values reduce packet overhead but increase the maximum latency. Smaller values improve
latency, but increase the packet overhead, which results in lower average throughput. The
default value is 2000 microseconds.
3.2.4 Forward error correction
Forward error correction makes the communication link more robust and reliable, at the cost of
maximum bandwidth. The following settings are available:
 None: No forward error correction is applied. This enables the highest throughput.
 2x bit correction: A codec that uses 2x redundancy to detect and fix bit errors
 1.5x bit correction: A codec that uses 1.5x redundancy to detect and fix bit errors
 Burst (+30) correction: A codec that can detect and fix burst errors. It adds 30 bytes to
the packet size. Burst correction is supported for serial baud-rates of 9600 bps and
19200 bps. Higher baud-rates can be used only if the average speed of data
transmission is below 19200 bps.

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3.2.5 Packet transmit mode
The packet transmit mode specifies the packet-level redundancy used to increase robustness of
the link.
 Normal: No packet-level redundancy is used (default).
 4.1 redundant: adds a 5th packet for every 4 packets for redundancy and error
correction.
 Dynamic retransmission: The modem continues to send packets to use the full available
optical bandwidth for the period of time specified in 3.2.3 Data wait time.
3.2.6 Beacon period
The beacon period is the time between beacon messages, that are used to instruct the receiver
not to go to sleep. Beacon messages are used to keep the receiving modems awake.
3.2.7 Auto off delay
If no beacon messages have been received for the time period specified in “Auto off delay”, the
modem enters a low-power sleep mode, with an average power consumption of less than 5
mW.
3.3 Sleep mode configuration example:
Using LumaConf, configure two modems as follows:
 on the modem A that should enter sleep (e.g. a modem installed on a sensor), change
"auto off delay" to 30 seconds (see 3.2.7).
 on the modem B that wakes up the other modem (e.g. on an ROV), change "beacon
period" to 2 seconds (see 3.2.6).
After changing settings, click "Refresh" to verify that the modem received the correct value.
Click "Save" to store the new value permanently in the modem’s internal flash. Then click
"Active mode" to leave config mode and put the modem into normal operation.
If modem A doesn't receive any beacon messages for 30 seconds, it will go to sleep. Current
consumption is then approximately 5 mW. When it receives the beacon messages from modem
B, it will wake up. As long as it keeps receiving "beacon" messages, it will stay awake.
Note that strobing lights, or other sources of pulsed light interference, may also temporarily
wake the modem up. It will keep listening for beacon messages to fully wake up and go back to
sleep after 30 seconds. In rare circumstances, this could be an issue, e.g. if the modem is stored
under a flickering light for extended periods, as it will be woken up continuously as soon as it
goes to sleep. The current consumption in this case would be around 25-30 mA, until the
interference source is removed.

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3.4 Firmware update
 confirm that communication with the modem is established as described in 3.1
Connecting the modem
 turn off the power supply to the modem (or unplug the SubConn connector, but leave
the serial dongle in the USB port)
 set the serial port settings to 115200 bps (at the very top of LumaConf, the speed for
your COM port, not the settings of the modem)
 click "Firmware update". A new dialog opens.
 switch on power to the modem (or plug it back in).
 Now, an entry should appear under "Devices". On the right-hand side are a few options,
you can ignore most of them.
 make sure that under "Firmware", the entry "LUMA100 - RS232 <…>" is selected
 click "write Flash"
 wait until the progress bar reaches 100%. If it doesn't go through, click "Write Flash"
again until it does complete.
 click "Start application". You should now be able to connect to the modem again as
described above. Verify that the modem settings are still correct - they should carry
across firmware updates in general, but bigger updates may invalidate the settings and
revert to factory defaults.
4 Maintenance
Please wash the modem with warm water (only) to remove any built-up which could negatively
affect its operation. Apply a thin film of silicone grease to the rubber part of the connector pins
to protect the connector and to facilitate mating. For maintenance details regarding the
connector follow SeaConn's instructions.

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5 Electrical and Software Characteristics
Supply voltage (Vs) 12 V – 36 V
Power consumption < 5 mW (sleep mode)
0.5 W (active mode, receiving)
1 – 3 W (active mode, transmitting)
Range up to 2 m (6 ft 6”)
Data rate (wire) Software selectable:
9600, 19200, 38400, 57600, 115200
Transmission power 1 banks with 3 LEDs
Interface Software selectable:
RS232
RS485
Emission wavelength 475 nm
Beam pattern 120 degree cone
Connector pinout 1: Supply voltage (Vs)
2: GND
3: RS232 RX / RS485 D+
4: RS232 TX / RS485 D-
5: n/c
6: n/c
Error correction Software selectable:
Forward error correction, overhead 2:1
Forward error correction, overhead 1,5:1
Burst error correction
Auto sleep Software selectable:
0 (= off), 1 – 60000 seconds
Beacon signal interval Software selectable:
0 (= off), 1 – 120 seconds

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6 Mechanical Characteristics
Length x Width x Height 100 x 50 x 30 mm (3.9" x 2" x 1.2")
Weight in air 250 g (8.8 oz)
Weight in water 50 g (1.76 oz)
Connector SubConn MCIL6M
Depth rating 6000 m (19000 ft)
Disclaimer: HYDROMEA ASSUMES NO LIABILITY WHATSOEVER AND DISCLAIMS ANY EXPRESS, IMPLIED OR STATUTORY WARRANTY
RELATING TO ITS PRODUCTS INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE, OR NON-INFRINGEMENT. IN NO EVENT SHALL HYDROMEA BE LIABLE FOR ANY DIRECT, INDIRECT,
ONSEQUENTIAL, PUNITIVE, SPECIAL OR INCIDENTAL DAMAGES (INCLUDING, WITHOUT LIMITATION, DAMAGES FOR LOSS OF PROFITS,
BUSINESS INTERRUPTION, OR LOSS OF INFORMATION) ARISING OUT OF THE USE OR INABILITY TO USE THIS DOCUMENT, EVEN IF
HYDROMEA HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

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7 Errata
Version
Release date
Errata
1.0
1.4.2021
Original version
1.1
22.12.2021
 Updated logo
 Added Errata
 Updated links to LumaConf
1.2
7.4.2022
 Updated link to LumaConf