8 Motor Primary / Standby

Does anyone have any tricks up their sleeves using ladder/ ST / FB (RS5000) for programming an 8 Motor rotation 1 Primary (7 Standby). Operator needs to be able to select the order from an HMI. Once the primary motor fails depending on the operator next selection any of the remaining 7 motors could be that standby #1 then that standby would have a stand.by #2..etc.

I know I could do it through hardcoding but there are way too many different combinations which does not sound very appealing.

I got two examples for 5 pumps, you can try to modify them.

Thanks, I have done that logic before. This one is different in that it won't alternate in order(1,2,3,4 // 2,3,4,1 // 3,4,1,2)..ETC... The operator may select 1,3,5,7,2,4,6,8 or 8,2,5,3,1,7,6,4.

So there are tons of different combinations they may select. In any randomized order that can be thought of.

I ended up making a UDT with one member of a BOOL[Array] - Used another UDT with the BOOL UDT with other bits and the selections for the Primary / Standby setpoints.

Then used a FLL to clear the BOOL[Arrays] then just used XIC -- OTE following the FLL.

(OTE)PumpSelection.Selected_LeadPump.BOOLS[PumpSelection.SP_HMI_Lead_Pump]

Then used the following rungs using the same theory if Primary is no longer available then

(XIO)PumpSelection.Pumps_Available.BOOLS[PumpsAvailable.SP_HMI_Lead_Pump]

(OTE)PumpSelection.Selected_Standby1.BOOLS[PumpSelection.SP_HMI_Standby_Pump1] -- ETC. got it all done in 9 Rungs then.