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--- ve.can:changing_nmea2000_instances [2019-08-15 12:17] – replace venus-device with GX device guy_stewart
+++ ve.can:changing_nmea2000_instances [2020-06-27 21:26] – [4. Changing Instance Using Maretron N2KAnalyzer] mvader
@@ Line 8: / Line 8: @@
 For the displays to show these values at the right place, they need to know which voltage belongs to what battery.
+Before going ahead and change instances, please make sure to first study [[https://www.victronenergy.com/live/ccgx:start#marine_mfd_integration_by_nmea_2000|the NMEA2000-out chapter in the GX manual]].
 === How can I change the instances? ===
@@ Line 17: / Line 19: @@
   - From the [[open_source:ccgx:commandline|commandline]] of a [[venus-os:start|GX device]]. Note that this is a software developer trick. Not for any day use.
-=== Device instance vs the data instances ===
+=== Device instance, data instances and other instances ===
-There are two types of instances: device instances and data instances. And depending on the make and model of the displays being used (Garmin, Maretron, Raymarine, etcetera), you need to change one of them or both.
+There various types of instances. Please make sure to study [[https://www.victronenergy.com/live/ccgx:start#marine_mfd_integration_by_nmea_2000|the NMEA2000-out chapter in the GX manual]] before continuing.
-Both the device instance and the data instance of a product can easily be changed with both Maretron N2Kview as well as and Actisense PC software.
+In summary, and as per NMEA2000 specification, it should not be necessary to change a data instance such as the DC instance.
 === Required hardware ===
 Changing the device instance requires an usb-canbus adapter to link the CAN-bus network to your computer:
@@ Line 29: / Line 32: @@
 === Related information ===
 For more detailed information, see also the FAQ in our [[https://www.victronenergy.com/upload/documents/Whitepaper-Data-communication-with-Victron-Energy-products_EN.pdf|Data communication whitepaper]].
@@ Line 52: / Line 56: @@
   - Open Actisense NMEA Reader
   - Select data view (tab selection is at the bottom left)
-  - Right click the PGN: \\ {{:ve.can:data_instance_0.png?direct&}}
+  - Right click on the PGN number. Note that this will only work on PGNs that allow changing their data instance: \\ {{:ve.can:data_instance_0.png?direct&}}
   - And change the value: \\ {{:ve.can:data_instance_1.png?direct&}}
@@ Line 62: / Line 66: @@
 ===== 4. Changing Instance Using Maretron N2KAnalyzer =====
-Maretron understands that it is sometimes difficult to know whether a particular product uses device instance or if it uses data instance to uniquely identify itself on an NMEA 2000 network. For this reason, Maretron uses a term called "Unique Instance" where the N2KAnalyzer software tool automatically determines if a particular device uses device or data instances.
+Maretron uses a term called "Unique Instance" where the N2KAnalyzer software tool automatically determines if a particular device uses device or data instances.
+WARNING: At Victron we do not understand what and how the Maretron software works with regards to this. We advise to use another tool, not Maretron, so that you know what you are doing, ie know what instance you are changing. So far, we have not been able to use Maretron software to change a data instance. And changing the other instance, the device instance can also be done straight from the Victron GX device its user interface. To change a data instance, for example to fix instance conflicts as reported by the Maretron software, we recommend to use Actisense. Not Maretron.
 Open N2KAnalyzer and make sure that the "Unique Instance" column is turned on (i.e. checked) using the Setup>Columns menu item.