olavespedal
Member
Hi,
pretty fresh to PLC's, but been on a drilling rig last few days with automated machine control and monitoring. Main purpose to assist new personell on machine control, but there have been some bugs making it neccessary to use Step7. The issue im asking about here is not one of the bugs really, but for me it's the one thing I can't figure out.
There were a problem with a parameter that is calculating movement of a wire, times the load on the wire as a measure for the wear on it.
The PLC code was designed to calculate the absolute value of:
("previous position" - "current position") and multiply it with load given in tons and divide the result on 1000, and then iterate like this until the temporary value reaches 0.2 and then add this value to a parameter that keeps on accumulating and reset the temporary back to 0. I don't want to copy the actual code since it's company property. The initial problem was that the value didnt update in the GUI. I found that the temporary value was stuck at some weird looking value (1.!QQ or something like that was the floating-point representation). I went into the db and put the value to 0 and downloaded the db to the plc and that fixed the problem.
The value is updating correctly, so user wise it's no problem no more, but for some reason the value shown in the GUI is not the same as the value I can monitor in the database that the result is being transfered to using Step 7. They keep updating with the same rate, but the value in the database is higher than the one in the GUI. It's also possible to adjust the value in the GUI, but this doesn't cause the values to be in sync.
Anybody know if this is a generic issue in this field and can give me some hints about what might cause this issue? Any help would be highly appreciated!
pretty fresh to PLC's, but been on a drilling rig last few days with automated machine control and monitoring. Main purpose to assist new personell on machine control, but there have been some bugs making it neccessary to use Step7. The issue im asking about here is not one of the bugs really, but for me it's the one thing I can't figure out.
There were a problem with a parameter that is calculating movement of a wire, times the load on the wire as a measure for the wear on it.
The PLC code was designed to calculate the absolute value of:
("previous position" - "current position") and multiply it with load given in tons and divide the result on 1000, and then iterate like this until the temporary value reaches 0.2 and then add this value to a parameter that keeps on accumulating and reset the temporary back to 0. I don't want to copy the actual code since it's company property. The initial problem was that the value didnt update in the GUI. I found that the temporary value was stuck at some weird looking value (1.!QQ or something like that was the floating-point representation). I went into the db and put the value to 0 and downloaded the db to the plc and that fixed the problem.
The value is updating correctly, so user wise it's no problem no more, but for some reason the value shown in the GUI is not the same as the value I can monitor in the database that the result is being transfered to using Step 7. They keep updating with the same rate, but the value in the database is higher than the one in the GUI. It's also possible to adjust the value in the GUI, but this doesn't cause the values to be in sync.
Anybody know if this is a generic issue in this field and can give me some hints about what might cause this issue? Any help would be highly appreciated!