In post #8, he did state that both inverters are driven by 4-20ma, although he stated it would run at 60hz, I often look beyond this, as my experience of 37 years has taught me someone will want to change speeds or operation of the plant even if they don't realise it, so I tend to make it easy. I worked for a very well known global food Mfg company ( not mentioning the name but has plenty of varieties lol) many times over a 16 year period, one project was for a plant that produced certain types of product, the brief was it will have two recipes where some ingredients would be added more than one time during the process, the recipe structure I adopted was that any product addition would be standard i.e. rather than stage 1 being a certain type like water, veg or whatever, the structure was such that the stage had a type of addition field, this was just a selection of types i.e. water, veg, manual, sugar etc. The rather new process engineer on the project gave me a right dressing down about the recipes he stated there are only two recipes for this plant & you have not followed out brief. to cut a long story short, we commissioned the plant, some 6 months later he called me up & said we need to add two more recipes, I asked if there was any new plant involved & the answer was no, I said I have no need to come to site, you just select the process that you want in that step & the parameters, he then apologised for his rant previously, realising that the way I configured the recipe made it flexible enough to cater for any recipe that did not need any other mechanical mods, he did ask me about if they need extra types of addition, I told him there were at least an extra 10 recipe stages should they be needed, simple to implement, the only changes would be text fields for the drop down lists & new blocks of code for extra plant. So if production say they only need this it usually means we will want more in the future.
Of course there is the other side of the coin where we have had to take out access to certain functions & make them fixed to stop people from altering things, no matter how you try, it always appears someone will find passwords or a way to defeat it, that also applies to people who are authorised to make changes but think they know better.
Of course there is the other side of the coin where we have had to take out access to certain functions & make them fixed to stop people from altering things, no matter how you try, it always appears someone will find passwords or a way to defeat it, that also applies to people who are authorised to make changes but think they know better.