Latest Start / Latest Finish dates not correct on NWA's

[Former Member]

Hi Experts,

I am implementing PS planning and at the NWA I have backward planning, with constraints as in, or similar to, the picture below. My start dates are all correct. My finish dates are all wrong. They are just duplicates of the start dates. I have my NWA's linked with pred and succ links with 100% interval such that the pred NWA should be fully complete before the succ can be scheduled. I have FS for all the links. I have a single shift 8 hour work center. The NWA Work / Number of resources / Percent calculate the Normal duration correctly and transfer it to the Work field on the Dates tab correctly. I have not populated the Min duration field in Scheduling ( I tried that and it had no effect).

Can anyone shed light on why my finish dates (both earliest and latest) are wrong?

[S0022314014 · Accepted solution]

Hi Kevin

Several things might be causing this:

• Did you run SCHEDULING ( CTRL+F9)?
• You may check the formulas in work center. Go to CR02, Scheduling TAB, check the otehr formula - standard formula used here is SAP004 unless you have specific requirements.
• Another reason might be, if the control key that you used has the scheduling box checked. (Go to INTENAL TAB - Select the Ctrl Key --> Click on Detailed Inofrmation)
• If the NW activity has been assigned to WBS elements, and if the WBS scheduling profile does not have the setting "Network Determines Date" then WBS element dates will impact the dates on NW activity.

Cheers

Savas

[Former Member · Accepted solution]

Hi Savas,

I already tried scheduling. I do have NWA determines the dates. I had the control key setting on, I turned it off and the dates did not change so I turned it back on. I am looking at the formulas now.

Thanks,

Kevin

[S0022314014 · Accepted solution]

Hi Kevin

Alittle bit more advice:

Now the Work center formula is useful if you are using the Calculation Key. Without duration, the scheduling will not be calculated properly. You havetwo options:

1) System calculates duration based on the following formula : WORK / NUMBER = DURATION. For this calculation to occur, calculation ket must be "Calculate X" depending on what do you want to calculate. For calculation of duration, you need to enter work, number and calculation key must be "calculate duration". If you want this formula not to be used, you can select "maintain manually".  

2) Ignore calculations/formulas in Work center headerr and enter normal duration manually.

Regards

Savas

[Former Member · Accepted solution]

Hi Savas,

I tried switching to the maintain manually. It didn't work. What is odd is that the duration did calculate on the scheduling section but didn't move to the dates section when I had calculate duration and a formula. It does similarly on maintain manually.

I have included some additional screen shots

[Former Member · Accepted solution]

Hi Savas,

You are correct. It is def related to the work center config and or master data. I went to another client that has my basic PS config but where I had yet to put in the WCTR. I entered the number of days and selected manually maintained and it worked.

Any advice on what to look for would be appreciated.

Thank you

[MTerence · Accepted solution]

Hi Kevin.

Do you need to maintain the constrains ? Try by removing it.

Also refer below note, check whether the mentioned scenario is similar for your case

1788945 - Incorrect duration on changing dates of an activity.

Regards

Terence

[kenmelching]

The scheduling algorithm runs off of the duration of the activity, not the work content.  The work sets the resource requirements and cost, but the duration is what is used for scheduling.  It sets a window in which to perform the work.

With 0 duration the start and finish are exactly the same instant.  You can use 0 duration to act like a milestone.

Enter a realistic duration and run scheduling again.

[Former Member]

Hi Ken,

Thank you for replying.

My original settings were that the work center was populated, the work was set to 80 hours, the calc key was set to calculate duration, Number (of capacities) was set to 1, the Percent (Work percentage) was set to 100. When selecting the enter button the Normal duration was set to 10 days. The Work Center had one 8 hour shift. So in the Scheduling fields on the Internal tab the Normal duration was populating. It wasn't transferring to the Dates tab duration field.

The original settings are below:

[Former Member]

NOTE: There is one omission in the above screen shot, I had the Calculation Key set to "Duration".

[S0022314014]

Hi Kevin

I believe you are missing some other parameters in your work center. Can you test this:

• Remove the work center and enter some duration/work by using manual duration (you can use other calculation keys as well) and run "scheduling".  (In CJ20N - Edit - dates - Schedule) . Check the DATES TAB. Do you see any values on the field "DURATION" or "WORK". If values do not show up here, your start / finish dates will not be impacted. If the values are updated then go to the next step. If the duration field is not getting updated then try changing the unit of measure from D to H or HR... (Try to understand if there is a unit conversion issue. 
• Check the details of your work center Basic/Capacity Tabs including capacity details.

Basic Tab should have SAP0 as the stadard value key unless you are using it for some specific processes. Capacities TAB should have  SAP008 as Other formula. If you double click on any field on the very same tab, you will end up with capacity header sreen. You should have some CAPACITY value calculated. Select all three check boxes (some of these will definitely not have any impact on your scheduling) on the planning detauls sub-screen area. Enter start/end/brek times. Number of capacities, base unit of measure = H etc.