How to choose an NGW-1
Due to the incompatibilities between NMEA 0183 and NMEA 2000, an Actisense NGW-1 is needed to convert data between the two standards. Think of it as trying to have a conversation with someone who doesn’t speak the same language as you. It’s not going to work without a translator.
This article will help you decide which Actisense ‘translator’ is right for you.
‘What data do I need my NGW-1 to convert?’
This is the first question we need to ask in the steps to figuring out the right NGW-1, and to answer it, we need to look at the different firmware options that are available.
Which of the following statements in bold applies to you:
- ‘I do not need to convert AIS data’: The standard NGW-1 firmware should be used if AIS data conversions are not needed. The standard firmware communicates at 4800 baud. This is configurable.
- ‘I need to convert AIS data’: The AIS NGW-1 firmware should be used if AIS data conversions are needed. The AIS firmware communicates at 38400 baud. This is configurable.
Please refer to the NGW-1 Conversion List for details of all conversions that can be performed by the NGW-1 (and just as importantly those that cannot). Notice there are two conversion lists, one for the standard firmware, and one for the AIS firmware.
Due to the continuing expansion of NMEA 2000 as manufacturers add new features to their products, it is not always possible to create a conversion as an NMEA 0183 equivalent doesn’t always exist.
In the latest version of NMEA 0183 released in June 2012, there are 148 sentences with between 550 & 570 data fields. In total contrast, in the latest version of NMEA 2000 released in February 2015, there are 163 PGN messages and 1569 data fields.
How do I connect the NGW-1 to my NMEA 0183 and NMEA 2000 devices?
Now that we’ve decided how we want our NGW-1 to operate, it’s time to look at the mechanics. To do this we will assess each side of the NGW-1 independently.
NMEA 2000 side
The NMEA 2000 side only has an effect on our choice of product code if connecting to a Raymarine SeaTalkNG network. Connecting any NGW-1 to an NMEA 2000/STNG network is simple with ‘plug & play’ connectors.
NMEA 2000 and SeaTalkNG use exactly the same data but different physical network connectors. Therefore, you will need an adapter cable in order to connect the NMEA 2000 side of the NGW-1 to your SeaTalkNG backbone. The product code for this adapter cable is STNG-A06045.
The NGW-1-STNG ships with this adapter cable included in the box and with the standard firmware (discussed in the previous section). However, this adapter cable can be purchased as an accessory with ANY Actisense NMEA 2000 Gateway (like the NGW-1). Please ensure you ask for this cable at the same time as purchasing your NGW-1 as we cannot sell the adapter cable separately.
If you need to connect an NGW-1 to an STNG backbone but have AIS data that you need to convert, please read on…
NMEA 0183 side
- ‘I need to connect to NMEA 0183 devices/instruments’: In this situation you will need an NGW-1 that has a cable with bare wires on the end coming out of the NMEA 0183 side. This is known as the ‘ISO’ variant. The bare wires are for connecting to your NMEA 0183 devices. Full wiring instructions can be found in the user manual.
The ISO variant can be connected to a PC/laptop using a serial (RS232) cable if needed. If the PC/laptop doesn’t have a serial port, a USB to serial converter is needed. These cables can be purchased as accessories from Actisense.
If we remember our firmware choice from an earlier section of this article we can conclude with the required product codes as follows:
- Connection to NMEA 0183 devices required with no AIS data conversions needed = NGW-1-ISO
- Connection to NMEA 0183 devices required with AIS data conversions needed = NGW-1-ISO-AIS
We now know that it is possible to buy an STNG adapter cable with ALL Actisense NMEA 2000 gateways and that a version of NGW-1 pre-configured for AIS exists.Therefore, if AIS conversions are needed and the NGW-1 needs to connect to a Raymarine SeaTalkNG network, the simplest option is to purchase an NGW-1-ISO-AIS with adapter cable STNG-A06045 as an accessory.
- ‘I want to use the NGW-1 only with NMEA 0183 software on my PC/laptop’: The simplest solution in this situation is to use the USB variant, known as the NGW-1-USB.
- Unfortunately, the USB variant only ships with the standard firmware. If the AIS firmware is needed in an NGW-1-USB, this can easily be downloaded and installed from the Actisense website upon receipt of the device.
- As mentioned previously, the STNG adapter cable can be purchased with all Actisense NMEA 2000 gateways as an accessory.
‘I need to change the settings in my NGW-1’
In the majority of cases, configuration of an NGW-1 is not required as it communicates at the standard 4800 baud rate for NMEA 0183 devices (38400 for the AIS firmware) by default. All available conversions are enabled by default so the only conversion related configuration option is to reduce the number of conversions carried out by the NGW-1. Checking extra boxes in the PGN enable lists in NMEA Reader that weren’t initially checked will have no effect.
All available conversions being enabled on the NGW-1 should not cause conflicts as NMEA 0183 devices are usually good at recognising data that they don’t require and ignoring it. NMEA 2000 is also very good at handling data.
If the NGW-1 baud rate needs to be changed, or if you would like to reduce the number of conversions being performed by the NGW-1, this can be done via the ‘Hardware Config’ tab in our freely available NMEA Reader software.