Reading flow on a 24hr period

[Ones_Zeros]

Hello,
I was needing some help with a task i have
i will try to explain & be detailed

I'm using Wonderware software in our SCADA system

I have a flow meter and currently I'm reading this flow in our wonderware software, but its a flow reading at that current time. It doesn't account for any down time.

So what i want to do is take this same flow value & monitor it on a 24hr period,
from 10:00 to 10:00. so at 10:00 that next day it would reset and start back at zero & monitor again from 10:00 to 10:00.


How in Wonderware could I set this up?

I appreciate any direction at all on getting this started

thanks

 

[gclshortt]

http://www.plctalk.net/qanda/showthread.php?t=16137

This thread should help you out.

Regards,

 

[Ones_Zeros]

thanks but I couldn't get this to work

any other ideas?

i figured within wonderware there has to be a function that looks at the windows clock to either start a script so the flow would start the 24 hour monitoring process at 10:00 am

 

[AshleyParr]

why not do it in the PLC?

but yes check the hour, when it equals 10 log the value of your meter. When i last used intouch these were conditional scripts e.g. $Hour == 10

Ash

 

[Saffa]

Is it an instantaneous flow (i.e. litres per second) or is it already totalized, i.e . The value keeps incrementing over time?

 

[DwSoFt]

To me it sounds like he has instantaneous flow and he wants totalized flow now as well. I agree the plc would be better to do it. it is easier to do with a pulse input, but i know the newer Allen bradleys have a Function block to totalize off of 4-20ma instantaneous flow rate as well.

 

[Ones_Zeros]

Thanks guys, I agree 4-20 from meter into PLC would be better option
But we're this flow meter is at, it would take some work
Getting this done.

But if I can script this is Wonderware
I can do this, just needed some direction
On how to do this.

Yes this is an instantaneous flow, now I need to have
A 24hr total of this flow. I can take the flow divide it by 24
So I know what flow has been sent through the
Flow meter in a 24hr period. This would
Count for down time, were the other value don't.

So if I use the Wonderware function $hour == 10
How would I add to this script to monitor for
24 hours?

Thanks, hope this all makes since

 

[Dravik]

Do you currently do any data collection to any ODBC source? Because if you do, or could, this could be done by logging your instantaneous flow to ODBC on a predefined interval(say every minute) and then having your 24hour flow value be sourced from a ODBC query that uses an aggregate function to sum all the instantaneous values for a 24 hour period.
I did this about a decade ago for reporting flow for environmental reporting.

 

[AshleyParr]

If your reading the instant flow on in touch, is that not out of the PLC?

Anyway, 2 options I see:
1. Log the data & use a query (neat & tidy)
2. A bit of a messy script. If you wanted to to this you need to sample your flow meter every X seconds. As its instantaneous it changes frequently, try sampling every 1 second to start.

E.g.
Instrument reads in litres per minute. We sample every 1second

FlowIncrement = FlowRate/60
FlowTotal = FlowTotal+FlowIncrement

Now you need to do this in InTouch, messy & program intensive which is why I was suggesting the Plc.
Start off by sampling every second, data change script using $Second and use the code above.

Condition Script when $Hour ==10 AND $Mintute==0 AND $Second==0, THEN
FlowIncrement = 0
FlowTotal = 0

Also id probably move to tags so you can see previous day's total

Hope that helps,
Ash

 

[Ones_Zeros]

AshleyParr,
I may have misspoken, the flow comes into a TDS polling program & use OPC link to read the flow into our wonderware software.


This flow i'm referencing is a gas flow & TDS polls the meter what ever time frame you choose, usually these meters are polled every 5 minutes


since i what to start the 24 hour monitor of this gas flow at 10:00 to 10:00
can i still use the code you provided?

Code:
FlowIncrement = FlowRate/60
FlowTotal = FlowTotal+FlowIncrement

and this code here, will reset the monitoring at 10:00...right?

Code:
Condition Script when $Hour ==10 AND $Mintute==0 AND $Second==0, THEN
FlowIncrement = 0
FlowTotal = 0

thanks for you time & patience
its much appreciated!!!

 

[Ones_Zeros]

also
is the "FlowTotal" on line two of this script
the flow value from the meter (Flowrate)?
so i'd take the (FlowTotal = flowrate+flowincrement)
is this right?

Quote:
Code:
FlowIncrement = FlowRate/60
FlowTotal = FlowTotal+FlowIncrement

and the second part would start the monitor at 10:00 am
would this monitor it for 24 hours or would i have to add another line?

Code:
Condition Script when $Hour ==10 AND $Mintute==0 AND $Second==0, THEN
FlowIncrement = 0
FlowTotal = 0

thanks,

 

[diat150]

AshleyParr,
I may have misspoken, the flow comes into a TDS polling program & use OPC link to read the flow into our wonderware software.


This flow i'm referencing is a gas flow & TDS polls the meter what ever time frame you choose, usually these meters are polled every 5 minutes


since i what to start the 24 hour monitor of this gas flow at 10:00 to 10:00
can i still use the code you provided?



and this code here, will reset the monitoring at 10:00...right?



thanks for you time & patience
its much appreciated!!!

is the meter a totalflow? if so, the totlflow will already be doing this calculation for you.

 

[Ones_Zeros]

Yes, it is a totalflow
But it does not monitor from 10:00 to 10:00
The meter is setup to go from 12:00 to 12:00

So I'm assuming it resets at 12:00 each day

I need to start monitoring the flow from 10:00 to 10:00
& reset it at 10:00 am in Wonderware each morning

Thanks

 

[mendonsy]

OK?? Where does the meter get the time from? Why not just set the clock 2 hours fast?? (or two time zones ahead)

 

[Mickey]

Yes, it is a totalflow
But it does not monitor from 10:00 to 10:00
The meter is setup to go from 12:00 to 12:00

So I'm assuming it resets at 12:00 each day

I need to start monitoring the flow from 10:00 to 10:00
& reset it at 10:00 am in Wonderware each morning

Thanks

HMMM? I guess someone should say it.

Why not change the Total Flow?