Integration problems look technical and are usually definitional. Connecting before deciding which side is authoritative, and which side wins when numbers disagree, costs you confidence in both.
Items, BOMs and customers to ERP; work history and equipment data to MES.
02
Decide direction and frequency
Tabulate which data flows which way and when.
03
Align the result definitions
Make production quantity mean the same thing on both sides.
04
Design error handling
Decide how transmission failures, duplicates and after-the-fact corrections are handled.
Why projects stall here
MES and ERP run at different time resolutions. ERP changes when a transaction posts; MES changes when material and machines actually move. That lag cannot be removed. The goal of interface design is not eliminating it but making the resulting difference explainable.
The most common failure is managing the same data on both sides. If items exist in both and both can edit, they will diverge.
Procedure
Following the order matters more than perfecting each step.
STEP 01
Assign an owner per data element
Items, BOMs and customers to ERP; work history and equipment data to MES. One system of record each. The non-owning side reads and cannot edit.
STEP 02
Decide direction and frequency
Tabulate which data flows which way and when. Separating what genuinely needs to be real time from what is fine daily simplifies the build considerably.
STEP 03
Align the result definitions
Make production quantity mean the same thing on both sides. Differing treatment of trial, rework and scrap means the numbers will not agree however well you connect them. Document it.
STEP 04
Design error handling
Decide how transmission failures, duplicates and after-the-fact corrections are handled. Without a procedure for correcting an already-transmitted result, this will become an operational problem.
Common mistakes
Patterns that recur in implementation discussions.
Common mistake
Leaving the same data editable on both sides
The most common and longest-lived problem. Pick one owner and make the other read-only.
Common mistake
Defaulting to real-time interfaces
Not all data needs to be real time. Unnecessary real-time links only add failure points.
Common mistake
Skipping agreement on result definitions
You connect, then come back to "the numbers do not match". Agreement precedes integration.
Common mistake
Providing no correction procedure
Floors do need to correct mis-entered results. Without a procedure, someone ends up editing the database directly.
Checklist
Confirm these are in place before starting.
A table assigns a system of record to each data element
The non-owning side is configured read-only
Direction and frequency are defined per element
Production quantity is defined identically on both sides
Handling exists for transmission failure and duplication
A documented procedure exists for correcting results after the fact
Tools for this stage
The procedure is the same without any product. These shorten the steps.