- #Rslogix using tag as timer preset update
- #Rslogix using tag as timer preset Offline
- #Rslogix using tag as timer preset download
if you have a math instruction that's multiplying Tag_A by 2 and storing the result in Tag_B. Generally, this is limited to constant operands - e.g. "Fixed values" is not really an AB term, but you are correct in that some values cannot be edited in the instances. I didn't know that fixed values could be edited in the instances I'll have a look at that tomorrow- thanks. You then updated the preset in your definition, but as I have described above, this change will not push through to your existing instances unless you specifically request it to do so.
At that instant, the timer was created in all your existing instances, with a preset of zero. Taking a step back into why this happened to start with - what I suspect has happened is that you've created the new timer in your AOI definition ladder logic, and then applied the change with a timer preset of zero.
#Rslogix using tag as timer preset update
You'll also note that the timer preset in your definition logic will update with the new preset, and all new instances that you create from this point on will likewise get the new default value. Check the box and hit apply, and now whatever value you put in that "default" column will be copied to all existing instances of your AOI's. Change the default value in the Local Tags editor, and you'll see the "copy all default values" box become available. You'll notice that it matches the timer preset in your AOI definition ladder logic. The first item in the list is My_AOI_Timer.PRE, and you'll see its default value in the third column. Find your timer in the list of local tags, and click the little arrow to expand out the data structure. Instead of changing the timer preset in the TON instruction, open the AOI definition dialog box and select the Local Tags tab. The reason it's greyed out is because you made the changes in the AOI's ladder logic, not in the parameter editor. That's where that checkbox comes in handy. This is good design practice of course - if you have 200 instances already in your code, and each of them has had their timer preset adjusted according to their application, having them all of a sudden set back to default just because you changed the definition would be a terrible outcome! But, at the same time, sometimes you do want all of your 200 instances to be updated with the new "default" value. However, any instances that already existed will not be updated. Any new instances of that AOI you create after you adjust that preset will be created with the same timer preset as your definition. then the preset you specified is the default for that AOI. Set a preset in that TON/TOF/RTO instruction Assign "My_AOI_Timer" to that TON/TOF/RTO Within the AOI, put a TON/TOF/RTO on a rung Have a local AOI parameter called "My_AOI_Timer"
#Rslogix using tag as timer preset Offline
I just tried an offline edit to one of the previous existing timer presets but the instances don't show the change, although a logical edit is reflected in all instances.įor a timer, the default value is the value set in the definition. As the local tags show the correct (non zero) value for all timer presets in the offline version, I'd interpret those values as being the defaults.
#Rslogix using tag as timer preset download
If you perform the test above, that should confirm things one way or the other.įor what it's worth, I've never seen a download cause any such symptoms, but I've been caught out by the "copy default values" trick a few times!ĪSF, I did see the copy all default values option but it remains greyed-out and unchecked when the timer presets are altered.
So if your issue is as you described it, this may be unrelated - but it's plausible that you edited an AOI and downloaded it, then noticed the issue, and mistakenly thought the issue occurred when you downloaded, not when you made the edit. This would occur not when you downloaded, but when you clicked "OK" on the AOI definition editor. If the timer preset in your AOI instance has a default value of zero, and you updated the AOI with this option selected, all instances would be set to zero.
When you update an AOI for which there are existing instances, there is an option to "copy all default values of parameters and local tags whose values were modified to all tags of this instruction type". If you change the timer preset of one of your instances online, save the program, and download again, does it retain its preset?
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