for those who might be interested. you can make the sun 1000G2 work with emontx. so if you wish to make the grid limiting feature 3 phase suitable or to be able to turn on off and adjust power output it is possible using EmonTx ardunio shield.
simply swap the external port wire from the right side to the left side as shown . now it can be controlled by a digital pot i currently only have 10k digital pot but by 50% the unit is sitting at 100% load.
curious would anyone know of a digital pot that has 256 - 1024 steps that work in the 5K range that is suitable for arduino projects.
Note: the pot connected to this port will override all program features, to re-enable features you would need to unplug GTI then remove the pot then once it starts up again it will work as it was programmed – quick update: after another trial test it seams if using the 10k pot but only limiting it to 5k or less you can use both the programmed feature and pot control. if you pass 5k you lock the control to only using the digital pot