Running a Closed Loop System

Confirming Pick-to-Light Picks

Modern devices support barcodes and QR-Codes that are a natural choice for transaction confirmations.  In fact, the encoded data can be customized for each individual pick.

These options are not available on our Classic devices, however, and so feedback requires the user to set up his/her own server to receive feedback information.

For modern or classic device users that need callback confirmations, there is a hidden parameter that the user can add to the QueryString URL, called a transaction ID.  (The REST API also supports this parameter.) Pick 3/SKU:001256/140,c5,4/20/transactionID001

The transaction ID is chosen by the user to identify the particular call to the device.  This can be a random number, or it could be a counter, or it could be a nonce.  It’s up to the user to choose. (The REST API simply refers to this parameter as ‘nonce’.)

If the transaction ID is added to the URL, then after the picker presses the button on the device, SKU-Keeper will make a URL call to your server like this:

If the picker does not press the button (within the time limit specified in the initial URL call), SKU-Keeper will make a URL call to:

If the device was out of range, or there was some problem communicating with the device, SKU-Keeper won’t make a follow-up URL call. *

So one of three things will happen:

  1. An ack message is received (indicates the picker pushed the button)
  2. A nack message is received (indicates the device timed out)
  3. No response (indicates the device is out of range, device over-write, or some other problem) *

The prefix of the response URL above,…, is pre-approved and set manually in SKU-Keeper for your account.  It can be any URL prefix you choose, using HTTP or HTTPS.  Contact us to register your URL.

Warning:  If you choose to use a Closed Loop System setup, you need a very reliable communication system between your server and SKU-Keeper on the cloud.

* After we designed this system, some customers expressed a desire to get a response back to every request.  So, we added a feature that can send back a ‘lost’ message for devices that don’t produce an ack or a nack. Just let us know if you’d like us to enable this for your account.

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