Downtime tracking

When I worked in garland, corporate came in with they're own contractor and installed some ab 5000's to mirror specific sensors and PB's on our production lines. So that some enginneer in chicago could not only moniter our production lines running, but levels of production also.
one night I received a call from the plant engineer, who had just been called by corp. they wanted to know how a slow bulk line with a max production per shift 0f 2000 cases could be outputing 6000 cases in one shift. We went down to scope it out, they (production) had awitched to a new case design, brown box, large black square with a dark red design in the middle, we found out that the case counting sensor saw black as not there, so it counted each case 3 times. so we changed the case counter to a thru beam sensor, problem fixed but when we told the operators about it, they were very nervous knowing that someone was watching over their shoulders as it was.....lol
 
in logix5000 you can use a GSV instruction with a wallclock object to move system time (including year, month, day, hour, minute and second) into a tag (i think its a 7 dint array). Not at work PC right now to verify.
 
in logix5000 you can use a GSV instruction with a wallclock object to move system time (including year, month, day, hour, minute and second) into a tag (i think its a 7 dint array). Not at work PC right now to verify.

Is this possible with Step 7?

In step 7, I use the clock memory to count up every second. However, I have always thought that this can only be as accurate as the PLC cycle time. Is this true???
 
Last edited:
I just send the signals to the scada application where it is easy to work with time. I did however originally use s7 to calculate the downtime using the system clock but it got a but messy.
 
Is this possible with Step 7?

In step 7, I use the clock memory to count up every second. However, I have always thought that this can only be as accurate as the PLC cycle time. Is this true???

yes i think it depends on scan time but if you are scanning 8 or 9 times a second then the system second count should be accurate.

OkiePC,
how does scan time affect a GSV wallclock instruction??
 
hi simon,
i'm trying to implement a Function block in Rslogix5000 to get the OEE of a packaging line, if u have a code wich can help ,can u send it please?
thx
 
yes i think it depends on scan time but if you are scanning 8 or 9 times a second then the system second count should be accurate.

OkiePC,
how does scan time affect a GSV wallclock instruction??

Well, the scan time of the code which triggers the GSV would be the worst case, so a random number from near zero to the interval of that program, then add the execution time of the GSV instruction itself. If you want to remove the random and shorten the delay, use a hardwired input interrupt.

Earlier someone quoted me saying it is difficult in excel, it actually is easy, but not for people who don't understand binary conversions. If I share an excel sheet with DDE/OPC Code, I password protect the writes, and hide columns that hold references to my 'raw' tab where all the hotlinks (reads) are protected from casual users of excel.
 
Mine is very easy, we have four bottling lines, whenever a bottle is not going out of a line we wait for 1 minute then start a retentive timer (RTO), when production restart RTO stops but maintains its value. this happens over and over. At the end of the day or shift i got downtime accumulated in the RTO.
 
My approach is simple and effective, see post #23. It has been working with production rate and quality in order to get OEE.

widelto, I have programmed downtime counters in the same way as you described. Yes, that works, but managers would like to know reason and duration of each separate downtime. And how do you know that it is "real" downtime and not planned maintenance, or changeover, or cleaning etc.? How do you calculate OEE without knowing the reason of stop?
 
I did an OEE system over 13 production lines, most of the signals were already there Alarms running, packs per min, I added a new screen to each HMI so that the operators/Engineers could enter events like reason for stops etc. I just logged it all to an SQL database then produced an Excel template, the template contained SQL queries in VBA to access the data and format it onto the sheets. The production supervisors could query using the template to get the relevant data.
 

Similar Topics

I am using studio 5000 and Compactlogix controllers. I am wanting to track uptime and downtime on 3 different machines. It is setup already but...
Replies
26
Views
9,832
I am trying to build a Machine Downtime within the PLC. I was thinking to capture system time but I got tripped on how to store downtime start and...
Replies
17
Views
5,135
i have a few machines here at my shop that we want to keep track of the machines downtime due to maintenance, i have a 5/03 processor using RS500...
Replies
8
Views
2,461
Hello, I've been browsing the forum and doing internet searches but i haven't been able to make anything work. What i am trying to do is log how...
Replies
5
Views
2,143
Can someone help me? i want to know what is the exact time of the machine downtime. Which when i go the machine i can just take note of the time...
Replies
9
Views
2,261
Back
Top Bottom