How to use Real Time Clock (RTC) to get flow per every hour and Day on RSLogix500

Hi Able Engineers!
How can I use Real Time Clock (RTC) to get flow per every hour and Day on RSL0gix500, Assuming I want to see volume of Liquid that passed a flow meter every 1Hour and Day?

What signal do you get from your flowmeter? An continuous analog signal representing flow rate, a pulse signal per volume of liquid, or a totalizer value read over a comms bus?

This will determine your methodology for calculating your 1 hr and 1 day values.

Please Sir, educate me based on ''A continuous analog signal representing flow rate'', and ''a pulse signal per volume of liquid''

Hey Dan,
I'm mostly just guessing here, but I assume you are measuring how much fluid is going through a 'flowmeter'.

Somehow, somewhere, there must be a device which the PLC can query to get what the current flow is. Saffa would (I assume) be asking what sort of device is being used to get the flowrate.

The flowrate multiplied by the time should give one the amount of fluid which passed in that time - assuming the flow is constant and the pump was not shut off.

One could, I assume, write an interrupt routine that is triggered by the real time clock, every, say, ten seconds and in the interrupt routine if the pump has been running continuous read the flow rate, multiply it by ten seconds and add the amount of fluid passed to a memory location for storing the amount of fluid passed. Then every hour or every day take that number and pass it on as the amount passed per hour or day - resetting the memory location as necessary.
Poet.

Hi Mad Poet, and Thanks for responding and at same time sorry for my late response please!
My challenge is how to use RTC function of RSLogix, Could you please(during your free time) send me some screen shots of RTC usage in a program may be using this flow issue for illustration? If you can, I will be very grateful please.
THANKS IN ADVANCE.

Where possible, I will use Modbus or best available serial protocol to query the flowmeter totalizer value. This eliminates cumulative errors that are unavoidable when using analog signals. The next best signalling method is pulse counting. It will be precise but can suffer from an offset in there is an outage of power or signal and you miss some pulses. If you can tolerate some difference between what your PLC says the total is versus what the flowmeter totalizer reads then you should still totalize at a relatively quick frequency.

As for storing the total for each hour using the RTC, you will need to reference the RTC.HR word and watch for a change. Each time it changes, subtract the running total from what it was at the previous hour mark and stuff it into a register. Move the new (now) running total into the place for the previous hour.

If your totals are in units that can exceed the value that an integer can hold then you may need to use long integers or some other method to maintain a long running count. In general I avoid ever resetting the running total, but there may be cases where it is the most practical thing to do. I will try to set up the PLC logic so that the running total will roll over at the same point as the flowmeter display.

With all that said, we don't know what model of PLC or flowmeter you are using. Please give us the specifics.

IdealDan said:

Hi Mad Poet, and Thanks for responding and at same time sorry for my late response please!
My challenge is how to use RTC function of RSLogix, Could you please(during your free time) send me some screen shots of RTC usage in a program may be using this flow issue for illustration? If you can, I will be very grateful please.
THANKS IN ADVANCE.

Click to expand...

I'm not aware of an "RTC Function" in SLC 500 PLCs. The time data is stored in the system Status files. If you don't know what an analog input is, or what type of flow meter interface you are dealing with, then your best bet is probably to hire a programmer to do this for you.

Bit_Bucket_07 said:

I'm not aware of an "RTC Function" in SLC 500 PLCs. The time data is stored in the system Status files. If you don't know what an analog input is, or what type of flow meter interface you are dealing with, then your best bet is probably to hire a programmer to do this for you.

Click to expand...

The OP did not say which PLC he/she is using just RSLogix500.

What PLC are you(OP) using ? The MicroLogix (most anyway) series of controllers do have a "RTC" addresses.

You can do this without RTC. Use my logic here to create your own clock and take the flowrate and move it where ever you want.

I uploaded it here: https://uploadfiles.io/0uno2

Choose slow download option.

Mickey said:

The OP did not say which PLC he/she is using just RSLogix500.

What PLC are you(OP) using ? The MicroLogix (most anyway) series of controllers do have a "RTC" addresses.

Click to expand...

Please just any SLC500 PLC with RTC, I want to learn it and use emulator, no real plc here please. I want to know how to program such flow using Real Time Clock.
THANKS IN ADVANCE FOR YOUR HELP

Bit_Bucket_07 said:

I'm not aware of an "RTC Function" in SLC 500 PLCs. The time data is stored in the system Status files. If you don't know what an analog input is, or what type of flow meter interface you are dealing with, then your best bet is probably to hire a programmer to do this for you.

Click to expand...

Hi Dear!
Every Professional here Learned, I'm in my own Learning stage now, I will appreciate your input pls.

Thanks in advance