How Labels are Printed
- The customer must generate a valid ZPL Label string.
- "ZPL" (Zebra Programming Language) is a command-based language used by labelers and printers as a set of instructions that create the visual image that is printed on a label.
- The ZPL Label string will include instructions for printing the barcode(s), the alpha-numeric readout of the barcode(s), any other text present on the label, and instructions for positioning and sizing of all of those elements on the label.
- When we scan the product at a barcode scanner (positioned before the label printer), our system asks the customer to provide that ZPL Label string.
- "Our system" is typically either a PLC, a BOSS RTC, a ICW Controller, or an MC4 Controller.
- This is typically in the form of a 'label request', in which we send the customer a message that contains the barcode that we scanned.
- The barcode that we scan is typically the SKU, but can be any other barcode already present on the item.
- The customer sends the ZPL Label string to our system.
- This is typically in the form of 'label data', in which the customer sends us a message containing the barcode that we scanned above, alongside the ZPL Label string.
- Our system passes that ZPL Label string to the label printer.
- This communication is commonly over ethernet, directly between our system and the label printer itself.
- The label printer interprets the ZPL Label string, turning it into instructions that it uses to print the desired label.
- The label printer applicator is responsible for physically 'tamping' the printed label down, onto the top of the product.
- After being printed and applied, the resultant label is scanned at a 'verify scanner' positioned just after the printer.
- If the label is not readable, the product itself is typically rejected, requiring that the bad label be removed and the item be reprinted.
- Our system will often send the results of the above 'verification' to the customer, informing them that this specific item has been inducted into the rest of the building.
- This is typically in the form of 'label verify', in which we send the customer a message containing the newly-printed barcode, as well as some flag indicating that the item was allowed to be inducted into the building.
The Communication Path
- Customer -> Warehouse Software Solution
- Warehouse Software Solutions may involve any number among WCS (Warehouse Control System), WMS (Warehouse Management System), and WES (Warehouse Execution System).
- Sometimes referred to as 'Middleware'
- While Intelligrated does offer Warehouse Software Solutions, some customers elect to use their own instead.
- Warehouse Software Solution -> Intelligrated Control System
- Intelligrated Control Systems include PLC, BOSS RTCs, ICW Controllers, and MC4 Controllers.
- Intelligrated Control System -> Label Printer
- Common printers include Zebra (traditionally the ZE500) as well as Panther printers.
Example ZPL Label string
^XA
^FX Top section with logo, name and address.
^CF0,60
^FO50,50^GB100,100,100^FS
^FO75,75^FR^GB100,100,100^FS
^FO93,93^GB40,40,40^FS
^FO220,50^FDIntershipping, Inc.^FS
^CF0,30
^FO220,115^FD1000 Shipping Lane^FS
^FO220,155^FDShelbyville TN 38102^FS
^FO220,195^FDUnited States (USA)^FS
^FO50,250^GB700,3,3^FS
^FX Second section with recipient address and permit information.
^CFA,30
^FO50,300^FDJohn Doe^FS
^FO50,340^FD100 Main Street^FS
^FO50,380^FDSpringfield TN 39021^FS
^FO50,420^FDUnited States (USA)^FS
^CFA,15
^FO600,300^GB150,150,3^FS
^FO638,340^FDPermit^FS
^FO638,390^FD123456^FS
^FO50,500^GB700,3,3^FS
^FX Third section with bar code.
^BY5,2,270
^FO100,550^BC^FD12345678^FS
^FX Fourth section (the two boxes on the bottom).
^FO50,900^GB700,250,3^FS
^FO400,900^GB3,250,3^FS
^CF0,40
^FO100,960^FDCtr. X34B-1^FS
^FO100,1010^FDREF1 F00B47^FS
^FO100,1060^FDREF2 BL4H8^FS
^CF0,190
^FO470,955^FDCA^FS
^XZ
