February 17, 2025 Raymarine, your turn!
New firmware 1.11 for Voyage Recorder YDVR-04 adds diagnostic telemetry and improves bus voltage detection. Digital switching integration guide for Simrad published. Update 1.07 for J1708 Engine Gateway adds support for intake manifold temperature for KAD/TAMD and J1708 engines, and Extended Range Engine Oil Pressure for J1708 engines.
The Voyage Recorder constantly monitors the NMEA 2000 bus power voltage, and if the voltage drops below 10.5 volts, it will stop MicroSD card operation to prevent damage to the file system.
In the new firmware, we have added a telemetry feature: the Voyage Recorder is now able to report its status (including low voltage, memory card errors, audio recording problems, etc., see VII.22 in the User Manual for details) via the standard NMEA 2000 digital switching PGN 127501 "Switch Bank Status".
Unfortunately, the implementation of this PGN on major MFDs is rather slow, e.g. Maretron DSM series displays supported it out-of-the-box for more than 5 years, Garmin has it only on the latest 8000 and 9000 series, on Simrad NSX series MFDs it is partially broken, and Raymarine MFDs do not support it at all.
To enable YDVR telemetry on Simrad NSX (and possibly on latest B&G and Lowrance MFDs), upload the XML file with the digital switching system layout: go to Settings => Boat Network => Add Device => Add Digital Switch; in the window that appears, select your XML file twice: first in the "Removable Media" list, then in the "Available Configurations" list. Click Next, Next, Finish. After that, you should get a Digital Switching panel on the left side panel (see the screenshot above).
You can download the XML file here, but note that you need to replace the 64-bit unique ID of the Voyage Recorder in line 5 with the number of your own device. You can get it from CAN Log Viewer (see the NAME field in the "Address Claim" section of the "Device Properties" window here). For more details, see "Digital Switching Integration Guide for Simrad NSX", which also describes how to configure our Circuit Control YDCC-04 and Autopilot YDAP-04.
It's a shame that such simple things require so much effort, but it's good that it's finally possible. At least on Simrad. Raymarine, your turn!
In J1708 Engine Gateway, we support all data for J1708 and KAD/TAMD engines that are supported in NMEA 2000 standard. But that doesn't mean we can't make the product better. Although intake manifold temperature is not supported in NMEA 2000, we added INTAKE_MANIFOLD_TEMP setting (works for KAD and J1708 protocols), which allows to display it as one of supported temperature types on NMEA 2000 MFDs. It works the same way as the ambient temperature setting, see this article for details.
We have also added support for J1708 PID 19 "Extended Range Engine Oil Pressure". This data is used when PID 100 "Engine Oil Pressure" data is not available or has a maximum value.
Firmware updates for Voyage Recorder and J1708 Engine Gateway are available on the Downloads page.
February 3, 2025 Python Gateway 1.05 Update
We are happy to introduce an update that allows you to use NMEA 0183 interface wires to connect equipment controlled by pulse width modulation (PWM) or logic levels.
At the last trade fair in Dusseldorf, three Python Gateways were installed at our company's booth. One emulated a GPS receiver and sent real time and date to the NMEA 2000 network so that the sensors at our booth could accumulate measurement history. The second performed our classic example: measuring voltage on the NMEA 2000 interface and sending the measurements to the network as battery voltage data, making them available for display on multifunction displays.
The third Python Gateway took data from the NMEA 2000 network (time, battery voltage, environmental data from our sensors) and displayed it on a WS2812B 8x32 LED matrix (the matrix is available in different sizes, and also as a strip). The control feature is the serial transmission of a 24-bit color value for each LED using pulse width modulation over a single wire. A button was also connected to this Python Gateway to stop and start the data change on the matrix.
The NMEA 0183 interface is electrically an RS422B interface, which means that the TX+ and TX- outputs will show an inverse signal when a logic "1" or "0" is sent to the transceiver. Similarly with the RX+ and RX- inputs: the transceiver reads "1" or "0" depending on the difference between the signal levels, but RX+ or RX- can be connected to ground to read a single wire logic signal (see "II. NMEA Basics" in the User's Manual for more details).
Thus, although the modern NMEA 0183 interface has five wires, only one output and one input are available to the Python Gateway programmer. To access them, you can use the machine.Pin class, having previously deinitialized the UART, which also uses these pins:
import machine
uart_tx.deinit()
p = machine.Pin("tx", machine.Pin.OUT)
while True:
p.on()
time.sleep(0.1)
p.off()
time.sleep(0.1)
The code above provides on TX+ and TX- outputs a rectangular signal with frequency 5 Hz and current up to 100 mA, which allows direct control of a low-power relay. But it is much easier to get such a signal using the machine.PWM class without loading the processor:
import machine
uart_tx.deinit()
p = machine.PWM("tx", freq=5, duty=50)
while True:
pass
However, for the WS2812B LED strip, the output signal is more complex. A logic "1" is encoded by a high level of 0.8 us duration followed by a low level of 0.45 us. A logic "0" is encoded with a high of 0.4 us and a low of 0.85 us. For each pixel we need to encode 24 bits of color, 8 bits each for Red, Green and Blue. And pixels in our case are 32*8 = 256.
Especially for this purpose, in the class machine.PWM was added method send(), which accepts an array of bytes, where each byte (0..255) means the duration of the signal in consecutive cycles (0-100%). To send a "1" and a "0" for the WS2812B, we would need to pass two bytes to the function:
{ 255*0.8/(0.8+0.45), 255*0.4/(0.4+0.85) }
Such calculations are not difficult, but for optimization we added the function ydpg.bit2pwm(), which allows us to prepare a buffer for machine.PWM.send() in one call.
You can download the code for the running line used at the expo at this link (requires updating the device firmware to version 1.05).
To add something nautical to this article, we will share with you a recent case study where the NMEA 0183 port was used in a Python Gateway for its intended purpose.
We have received a request to connect an NMEA-0183 capable Lambrecht Weather Station WS6 to Transas Navi-Sailor 4100 ECDIS via NMEA 0183 port. However, there is a problem: the Weather Station outputs humidity data via NMEA 0183 sentence MHU, air pressure via MMB and air temperature via MTA.
Unfortunately these sentences are not supported by the 4100 ECDIS system, it expects these data to be sent via MDA "Meteorological Composite" sentence instead. So we have inserted YDPG-01 in between: YDPG-01 NMEA 0183 listener port to the Weather Station talker port and YDPG-01 NMEA 0183 talker port back to the 4100 ECDIS system listener port. Since NMEA 2000 is not used in this project, the YDPG-01 NMEA 2000 interface was used only to power the Gateway: a NMEA 2000 power TEE with only two power rails (+12 V DC) was connected.
The following Python program was written to extract data from incoming MHU, MMB, and MTA sentences and, when all three are received, to send all data values via a single MDA sentence:
# buffer for MDA sentence
mda_data = [b''] * 20 # MDA contains 20 fields, make buffer of 20 strings
mda_mask = 0 # bit mask, indicates which messges were received {MTA, MHU, MMB}
# parses received NMEA 0183 sentence
# with indication which data fields to extract
# when all MTA, MHU, MMB received, sends MDA
def clbk(index, line, mda_offset, field_count):
global mda_data, mda_mask
#split fields and remove talker ID
args = line.split(b'*')[0].split(b',')[1:]
if len(args) == field_count:
#copy received fields to MDA sentence fields
mda_data[mda_offset:(mda_offset+field_count)] = args
# mark received sentences [ MTA, MHU or MMB ]
mda_mask |= 0x1 << index
if mda_mask == 0b111:
# all messages received, send combined MDA
n0183.send(b'MDA,' + b','.join(mda_data))
# reset MDA buffer
mda_data = [b''] * 20
mda_mask = 0
# callback: when air temperature received
def mta_clbk(n0183, line):
clbk(0, line, 4, 2)
return True
# callback: when humidity is received
def mhu_clbk(n0183, line):
clbk(1, line, 8, 4)
return True
# callback: when barometric pressure is received
def mmb_clbk(n0183, line):
clbk(2, line, 0, 4)
return True
# send 'MDA' with talker ID = 'WI'
n0183.talker(b"WI")
# forward received messages to TX port
n0183.forward(True)
# register RX callbacks
n0183.rxcallback(0, mta_clbk, b'$WIMTA')
n0183.rxcallback(1, mhu_clbk, b'$WIMHU')
n0183.rxcallback(2, mmb_clbk, b'$WIMMB')
This program produces the desired output on the Python Gateway talker port by adding the MDA sentence:
$WIMWV,357.0,R,5.2,M,A*26
$WIMTA,-25.0,C*31
$WIMHU,100.0,,-40.0,C*15
$WIMDA,,,1050.0,B,-25.0,C,,,100.0,,-40.0,C,,,,,,,,*22
$WIMMB,,,1050.0,B*04
This program is rather simple and short, but it well illustrates several important techniques that can be very useful in YDPG-01 program development, like:
- interception of certain received NMEA 0183 sentences by "match mask" via n0183.rxcallback()
- binary flags and bitwise operations (mda_mask)
- crafting and sending custom and direct forwarding of received NMEA 0183 sentences
To start getting familiar with the Python Gateway, go to its page. The firmware update 1.05 is available at the Download section.
January 18, 2025 Visit us in Dusseldorf
We are pleased to invite you to the Busse Yachtshop booth E11 in hall 10 to see our new products in action.
This year we present a new Autopilot, which is compatible with all modern MFDs. It is a course computer and actuator control unit in one housing. It can control vessels up to 40" and 12 tons displacement, with a hydraulic pump or a reversible linear drive with electric clutch, providing 15A maximum continuous current (21A peak) and 12/24 volt supply. The new model, expected in the middle of this year, will have Wi-Fi on board so it can be managed from a smartphone without any physical buttons. It will also help with initial calibration and setup.
We are also excited to introduce a new generation of our popular sensors: Digital Barometer, Digital Thermometer, Exhaust Gas Sensor and Humidity Sensor. They are built on a new platform with a high performance microcontroller and Wi-Fi.
Sensors can create an access point or connect to an existing network. Built-in web server makes it easy to update firmware, customize the device or access measurement history for a minimum of 3 months of data. Wi-Fi can be completely disabled for security or power savings. Like the previous generation, the sensors can also be configured via CAN bus.
And of course, our new and beautiful Pyhon Gateway. It connects NMEA 0183 devices to the NMEA 2000 network and provides unbeatable data processing and filtering capabilities using the power of the Python 3 programming language and the Yacht Devices library.
We installed three devices at the Expo. One is to display NMEA 2000 data on the LED matrix. Yes, you can use the NMEA 0183 connection as usual pins and even run PWM on the outputs to control the matrix and use the input to connect a pushbutton (PWM library will be available for everyone in the next release in the next two weeks). The second emulates GPS (it's hard to run GPS under the roof of the Expo Center): it sends date/time data for sensors to maintain measurement history. And the third measures voltage on the CAN bus and sends it to the NMEA 2000 network as battery data. Of course, we can run all this code on one unit, but we are happy to have three.
If you can't attend the best holiday for all boaters in Europe, don't be sad. We've prepared two fresh catalogs in English and German, where you'll find more information about new products, as well as one brand new one we haven't told you about yet (see the last page).
Aleksandr Gorlach will be at the booth every day, but it is better to contact us in advance to arrange a meeting. Come to our booth, we look forward to seeing you!
Next articles:
- Merry Christmas and Happy New Year / December 23, 2024
- New model of Battery Monitor is released / November 25, 2024
- Improved generator support / July 31, 2024