Device serial number issue

Hi Guru,

we have multiple material code in current system,when creating device number in sap ISU system generating device number (is not unique) and equipment number unique.

when using  new material code system generates serial number 1,2,3,4

if i use different material code  system generates serial number 1,2,3,4 and using internal number range here.

so i am not getting unique device number here and getting Equipment number unique.

i am looking Device number and Equipment number should be unique.

Please guide me how to resolve this issue.

Thanks in advance.