Daily flow totalizer in MARK VI

Dear all,

Could you advise me how to creat a daily flow totalizer in MARK VI
Note: The totalizer should be cleared automatically every midnight

Kind Regards
 
HOUCINOS,

To my knowledge the Mark VI application code (the ”logic” or ”sequencing” or ”programming”) doesn't know about and can't make use of the date/time (day/month/year, hour/minute/second).

Yes; the Mark VI control processors can tag alarms and events with the date/time, but the actual program has no functions which are or can be made aware of time.

I have seen something similar done on the GE Mark* HMI using the programming capabilities of CIMPLICITY/PROFICY MACHINE EDITION. It's actually easier than doing it in the Mark VI and getting the points on EGD and then displaying the value(s) on the HMI--MUCH easier (in my personal opinion).

Now, this post might actually be about Mark VIe, which, I believe can make use of date/time information, or newer versions of Toolbox might be capable of using date/time information (I'm becoming something of a dinosaur in my waning career), but I was always told that the Mark* controllers we're purposely not made capable of using date/time information in order to try to prevent most types of perceived hacking attempts that were possible and known about at the time. That thinking may have changed, but it is one thing that distinctly separates the Mark* series of controls from many other programmable controllers which are or can be used for turbine control and which can be more easily hacked to cause damage and/or mayhem.
 
Actually, on the Mark VI there is the _UTC_TIME block under Timer_Counters in SBLIB (at least in the version I have, it may not have always been there). For the Mark VIe, there is the TIME_MON block which has additional capabilities.

I do urge you to carefully examine failure modes on any time-driven code running on your controller. Make sure it fails safe if the time jumps, moves backwards, or is just plain wrong.

Depending on what you're using the flow total for (ie extracting it from the system for logging or regulatory purposes) it might be better to have a running flow total and simply sample it at midnight in your historian and subtract the previous sample's value, and skip trying to reset it at a particular time.
 
Are you looking at Mark VI or Mark VIe? If it is Mark VI, your block choice is a little more limited. I would have a 24 hr timer and then reset the flow totalizer every 24 hours. However, on reboot of the controller, you will need to reset the timer based on UTC.
 
Are you looking at Mark VI or Mark VIe? If it is Mark VI, your block choice is a little more limited. I would have a 24 hr timer and then reset the flow totalizer every 24 hours. However, on reboot of the controller, you will need to reset the timer based on UTC.
MARK VI
 
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