How to save and read daily MAX and MIN values?

[john_s]

Here's my very 1st post and a question..

This project requires to read, store and display 4 current loop inputs (4 to 20mA).

The data needs to be kept and displayed in table format; where Format = Date + MAX_val(day) + MIN_val(day).

The other requirement is to easy read and scroll through those historical MAX and MIN values

using some sort of UP and DOWN scroll buttons or a toggle switch.

I'd appreciate any feedback and hardware suggestions.

Regards,

John

[Joe Tauser]

You'll need a V130 at minimum, and depending on the resolution you're looking for a V130-33-R6 would probably handle the job.

Read ALL the Help on Data Tables and the RTC to ASCII function. Then look at the System Integers to see where the clock registers are.

After you do this, take a swing at writing a program to meet your requirements and post it with further questions.

Joe T.

[john_s]

I focus on V350 to start with - yet the requirement is for 12-bit resolution.

To my knowledge it has is 10-bit A2D only - can I improve it somehow by adding an external 12-bit A2D?

[Simon]

OK, I responded to your other post before seeing this one. Now I see the whole picture. If you need 4 inputs at 12-bit resolution, I would suggest the IO-AI4-AO2. It also gives you 2 outputs that you don't need. The other option is the IO-AI8, which is slightly more expensive, but gives you some spare inputs.

As I mentioned in my previous post, check the sample rates in the module datasheets. The sample rate can vary depending on how many inputs are being used.

For the I/O modules, you also need one EX-A2X I/O interface module.

Depending on your other I/O requirements, you could use the V350-35-B1 if all your I/O is coming from external modules.

[john_s]

You'll need a V130 at minimum, and depending on the resolution you're looking for a V130-33-R6 would probably handle the job.

Read ALL the Help on Data Tables and the RTC to ASCII function. Then look at the System Integers to see where the clock registers are.

After you do this, take a swing at writing a program to meet your requirements and post it with further questions.

Joe T.

Thanks Joe, I'll read through and try to understand the details of ALL that you suggested.

This will be my very first attempt in programming the PLC using Unitronics tools so expect plenty of ooops...

I only had my hands on V350 demo unit some time ago, and now is the time to be serious about my application.

Regards,

John

[Joe Tauser]

John,

This is a complex first project for someone who hasn't done Unitronics before. You'll be using functions that don't even exist in other PLC's.

I always push the Help on somebody new because it's really good and there are a LOT of pictures. You won't be able to get the same level of understanding from a mostly-words-only format like this forum. If you can get your distributor to help that's even better.

It's important to post your program if your questions are deep because then we can look at what you've actually been doing to give the best advice.

Our goal is to make you as big a Unitronics fan as we are. It does require some study and practice on your part.

Joe T.