# Initial installation of a mME in an existing metering location — LF view The gMSB informs the LF of the intent and the planned time period of the first device replacement with a mME. The device replacement will take place within the planned installation window of no more than twelve months. Delimitation: the process does not apply in the case that - the initial installation is initiated at the customer's request (not due to roll-out) or - there is a technically required replacement due to a fault at the metering location or - the replacement takes place due to a short-term calibration law requirement (i.e. deviating from the plannable cycle) or in the context of failed random sampling. ## Process flow from the perspective of the LF \nSystem diagram: Ersteinbau einer mME in eine bestehende Messlokation — view of LF\n\n\nCustomer backend system\n\nMACO APP · LF\n\nMarket partner\n\n\n\n1. Vorabinformation zum\nGerätewechsel\n\nMSB (entspricht gMSB…\n\nAS4\n21029\n\nLoad data for the incoming\ncheck\n\n\nMesslokation lesen\n\nAPI\n\nAPERAK check: Z10, Z17,\nZ18\n\n\nCreate transaction\n\n\nCreate process data\n\nAPI\n"} gesamt={"\nSequence diagram: Ersteinbau einer mME in eine bestehende Messlokation — view of LF\n\n\nBackend (customer)\n\n\nMACO APP · LF\n\n\nMSB (entspricht gMSB am O…\n\n\n1. Vorabinformation zum Gerätewechsel\nAS4 · PI 21029\n\nCreate transaction\nCreate process data\n"} titel="LF" /> ## Process steps ### Advance information on the device replacement
**Check identifiers** - [21029](/en/schnittstellen/202604/pruefi/IFTSTA/PI_21029) — Advance information · AS4
**Flow**
  1. Message from **MSB (corresponds to gMSB at the metering location object)** · AS4
  2. **Load data for the incoming check** - [Read metering location](/en/api/202604/backend-lesen/getmeterlocationbasic#messlokation-lesen) `GET /getMeterLocationBasic` Try it
  3. **APERAK checks** - `21029` → `Z10` — APERAK check: Is location known ? - `21029` → `Z17` - `21029` → `Z18`
  4. **Write endpoint** - Transaction created — [Create process data](/en/api/202604/backend-schreiben-lf/createprocessdata#prozessdaten-erstellen) `POST /createProcessData` Try it out Creates a new transaction in the backend with the data of the incoming message.
## Process information Wording of the consolidated version, profile ch. 3.4.1, pp. 57–58.
  1. ### Error case #### Result in the error case If the initial installation of the mME could not take place within the installation time window and is still intended, this information is to be started again for a further initial installation. #### Error cases z.B.: - Access to the metering location not possible within the time period
  2. ### Further requirements The information obligations under § 37 (2) MsbG remain unaffected.
  3. ### First message **MSB (corresponds to gMSB on the metering location object)** sends “Advance information on the device replacement” (step 1). From here on, the party involved on this side is the one to act.
  4. ### Objective All LF are informed in advance about the intended initial installation of a mME in an existing metering location.
## Other views of the process The same process through the eyes of the other parties involved: the same steps, each read from their point of view. - [View GMSB](/en/prozessdoku/202604/MSB/WiM-Teil1-ersteinbau-einer-mme-in-eine-bestehende-messlokation) — default metering point operator · market role MSB *The steps are the **possible** messages of this process, not a sequence — the source lists neither conditions nor alternatives. The small box on the step names the own view on the left: with **←** it receives, with **→** it sends. Collapsed steps run between other market partners.*