Looks like you and I are trying to do the same thing. It seems that your simply looking to poll modbus registers, and write them. Here's what I found. There are two types of groups. Group one are experts at doing just this. Group two are experts at taking the data and putting it on a slick graph. I spent 6 months on this same project last year, only to get frustrated and quit. I think we should collaborate. Drop me an email response. Thanks. Greg