Acknowledgements | HL7 v2 Codec for Azure Logic Apps

Two kinds of ACK

On receipt: Decode builds the ACK (generateAck, on by default) from parsing and validation. Return ack right away.
After processing: turn generateAck off, process the message, then build an application ACK with Create HL7 acknowledgement, for example AE when storing the result failed.

Create HL7 acknowledgement

Input	Default	Meaning
`message`	(required)	The message being acknowledged (or a batch, for a batch ACK).
`ackCode`	AA	AA, AE, AR, CA, CE or CR.
`errorMessage`		Text for the ERR segment of a negative ACK.
`errorCode`	207	HL7 table 0357 code.
`ackSendingApplication, ackSendingFacility, wrapAckInMllp`		As for Decode.

Output: success, ackCode, ack and errors.

"Application_ACK": {
  "type": "ServiceProvider",
  "inputs": {
    "parameters": {
      "message": "@{triggerBody()}",
      "ackCode": "@{if(equals(outputs('Saved'), true), 'AA', 'AE')}",
      "errorMessage": "Could not store the result",
      "errorCode": 207
    },
    "serviceProviderConfiguration": {
      "connectionName": "lamboHl7Codec",
      "operationId": "createAck",
      "serviceProviderId": "/serviceProviders/lamboHl7Codec"
    }
  }
}

What ACKs contain

Sender and receiver swapped, MSA-2 = the message's MSH-10, written with the inbound message's own delimiters.
ERR segments in the v2.5+ layout, or ERR-1 for v2.4 and earlier.
Enhanced mode (MSH-15/16 present) produces commit ACKs (CA/CE/CR) when ackMode is Auto or Enhanced.