PLC Help

I am working on a project that is basically opening and closing 8 different valves and using a mass flow meter. Where i am having difficulty is due to how to the read information that the end user will input into an HMI. The end user will have a screen with 8 different chemicals listed. The user will have to input numbers 1-8 specifying the order that the chemicals will be introduced into a mixer. The next information is the amount of pounds for that chemical. I am trying to figure out how to get the PLC to read, for example, the first line of information and read the order of chemical and how much weight. If you have questions in order to help me please let me know. thank you

What plc and HMI? That will determine what tools and methods you have available to you.

Keith

I will be using a 1214C DC/DC/DC Siemens PLC with a TP1500 Comfort Siemens HMI

That plc is a little outside of my comfort zone but I know you can do this with it.

I would set this up as an array of structures. The array size would be based on the greatest number of chemical additions you need to make. The structure would have (at least) two elements:
the number of the chemical to add
the quantity to be added.

You can display the information on the HMI in two ways. The first would be to display the total contents of the array on a single screen, basically two columns and as many rows as you have array elements. The user could then access any recipe item directly.
The other method would be to display one array element at a time, the chemical number and the amount to add, and cycle through these one at a time to access them.

Keith

i thought about using arrays but i am a bit unsure on how to get started

You can make an UDT of the rows with two values, like kamenges said.
And this you can put in an array in DB.

Something like this, though in the TIA portal


This then can be added into the HMI.
ie

for something simple like this would use 16 i/o fields