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Author's profile photo Himanshu Goel

Reference Designators for Electronics Industry

This scenario pertains to Electrical & Electronics industry where it is important to store Reference designators in SAP.

As per Wiki “A reference designator unambiguously identifies a component within an electrical schematic or on a printed circuit board. The reference designator usually consists of one or two letters followed by a number, e.g. R13, C1002. The number is sometimes followed by a letter, indicating that components are grouped or matched with each other, e.g. R17A, R17B. IEEE 315 contains a list of Class Designation Letters to use for electrical and electronic assemblies. For example, the letter R is a reference prefix for the resistors of an assembly, C for capacitors, K for relays.”

Please refer Wiki for more details on Reference Designators:

While working in Electronics industry it is important to store these Reference Designators in SAP and eventually send this information to connected MES systems. This information will help the MES system to place the component at the exact mounting points on the PCB. As shown in the picture below, reference designators are marked on the PCB. This marks the exact place where a component for example a capacitor or a relay, should be placed on the PCB. Also, same components could be used at multiple points which means a component can have multiple Reference Designators which makes it even more important to store all the reference points for each component in SAP.

Reference designators can also be called as Mounting Points or Installation Points.

Now the question arises where to store these Reference Designators in SAP?

Well, all the component details are stored in BOM so it makes sense to store Reference Designators in BOM.

Click on ‘Goto’ in the Menu bar and then click on ‘Subitem Overview’


In the BOM sub-items section, we can store the Reference Designators which are called as ‘Installation Points’ in SAP.

What we need to remember is that the quantity assigned for the sub-items will eventually over-write quantity defined at the component level.

Thus, Reference Designators can be stored very easily in BOM’s within the standard SAP system and there is no need to maintain Z-tables or enhancement to BOM.

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      Author's profile photo Lawrence Joy
      Lawrence Joy

      I really dislike it when organizations put out bum information. For class designation letters you should not reference or go by wikipedia as they have unorthodox class letters listed. You should go by and reference the source, which is IEEE 315, Clause 22.4. You can also see my postings about reference designations at

      It also looks like you have a penchant for the Block Numbering Method of assigning reference designators, which is deprecated. See ANSI/ASME Y14.44 for the Unit Numbering Method of assigning reference designations.

      Thirdly, according to ANSI/ASME standards the term BOM (Bill-of-Material(s)) is deprecated. The term to use is parts list (PL).

      --Regards, Larry

      Author's profile photo MAHENDRAN PARAMASIVAN

      Hi Thanks for sharing the information. it is very useful. Please post these kind of contents more.