Warehouse Order Picker Terminal — WMS Pick Instructions and Barcode Capture at the Rack Face

1. The Operation

The facility handles palletised and case-picked goods across a racked area with aisles between 1.8 and 2.4 metres wide. Order pickers are used rather than counterbalance forklifts because the operator platform rises with the forks — the picker travels up to the rack face at the required level instead of using a reach truck and then climbing.

Each order picker carries one operator for the duration of a shift. A shift covers 8 hours with pick rates measured in lines per hour. The operator platform has a control console with the travel and lift controls, and it is this console that is the natural mounting point for a display — the operator is standing at it for the whole shift, and it moves with the platform as the machine rises.

2. Where the Paper Workflow Broke Down

The first failure was the mid-shift pick list change. When an order was amended or a priority shipment arrived, the WMS re-sequenced the pick order. The printed sheet on the operator platform no longer matched the system. The picker either continued with the original sequence and created a delay at the dispatch lane, or returned to the office for a new printout — which on a narrow-aisle machine means driving back out of the aisle, down to the floor, and back again.

The second failure was manual keying. Completed pick sheets were collected at the end of the shift and entered into the WMS by office staff. Between the physical pick and the digital record there was a delay of up to 8 hours, and a manual transcription step. Stock accuracy reports run at the end of the shift did not reflect the actual state of the racking — they reflected the state of the keying queue.

The third failure was damage claims. When a case arrived at a customer with a damaged outer, there was no record of what the case looked like when it was picked. The picker had no way to photograph the case at the rack face and attach the image to the order line. Claims were resolved by argument rather than by record. The warehouse tablet platform is specified for exactly this class of workflow — a mounted terminal that runs the WMS client and captures data at the point of work.

3. What the Mounted Terminal Does

The terminal is not a screen showing a PDF of the pick list. It is a computing platform that runs the WMS client directly. Three functions run on the same device:

Because the terminal is connected to the WMS continuously, a re-sequenced pick list appears on the screen within seconds. The operator does not leave the aisle. The pick sequence follows the system, not the printout.

4. Data Capture at the Rack Face

Two data capture methods are used on the order pickers, for two different purposes.

Barcode scanning handles the location and item confirmation. The rack face carries a location label; the case or pallet carries an item label. Both are read with an integrated 1D/2D scan engine. The scan engine is either built into a handheld reader connected to the terminal, or integrated into the dock as a fixed module — the choice depends on how far the operator needs to reach from the platform. For cases picked from the rack at arm's length, a handheld reader connected to the terminal is sufficient. For pallet locations where the operator leans out from the platform, a dock-mounted scanner with an extension is more practical. The barcode and RFID integration options for warehouse terminals cover both configurations. The MDT1065 supports LF RFID modules and 1D/2D scan engine expansion through its dedicated accessories.

LF RFID reading handles asset and container identification where a barcode label is not practical — returnable plastic containers, metal stillages, and tooling that passes through the warehouse repeatedly. The terminal uses an LF module at 125–134 kHz. LF reads at short range, typically 2 to 10 centimetres, which means the operator brings the reader close to the tag. The reason LF is used here rather than a higher frequency is the material the tag is attached to: LF is significantly less affected by metal and liquid than UHF. Returnable containers with metal frames, or containers holding liquid product, read reliably at LF where a UHF tag on the same container would be detuned.

This is a frequency selection decision, not a preference. If the deployment requires reading pallet tags at a distance — for example, an automated read portal at a dock door — LF is the wrong technology because of its short range. The frequency must be matched to the tag type, the mounting material, and the required read distance before the terminal is specified. A warehouse terminal selection guide covers the RFID frequency trade-offs in more detail.

5. Connectivity Inside Steel Racking

A racked warehouse is a difficult radio environment. Steel uprights and horizontal beams reflect and absorb 2.4 GHz and 5 GHz signals. A dense racking layout creates a series of partially shielded pockets at each rack bay. The WMS data link must survive this — a dropped connection means the pick instruction on the screen stops updating.

The deployment uses WiFi with fast roaming as the primary data link. The access points are positioned so that a machine travelling down an aisle sees overlapping coverage between adjacent APs, and the terminal hands over between them without dropping the session. This is the link that carries the WMS data — pick instructions, confirmations, and photographs.

4G LTE is available as a fallback for areas where WiFi coverage is marginal — typically the far end of long aisles, or the yard if the machine is used for loading. The terminal switches to cellular when the WiFi link degrades, and back when coverage recovers. This is a continuity measure, not the primary link.

LoRa is used for a separate network. It does not carry WMS data — LoRa is a low-bandwidth modulation and is not appropriate for the data volume the WMS client generates. It carries low-rate telemetry from battery-powered sensors in the warehouse: pallet-level condition sensors, or environmental monitoring in areas where a fixed sensor installation is impractical. The LoRa module mounts on the rear expansion interface of the terminal, so the same device that displays pick instructions also acts as a LoRa gateway as the machine moves through the building. This is a useful side effect of using a general-purpose computing platform rather than a fixed-function terminal.

6. Onboard Scale and Serial Peripherals

Some pick workflows require the weight of the picked goods to be captured alongside the quantity. The order picker carries an onboard scale on the platform, connected to the terminal through an RS232 serial interface. The weight reading is displayed on the same screen as the pick instruction and written to the WMS record alongside the barcode confirmation.

This is where the serial interface matters. A scale with an RS232 output cannot be connected to a device that only offers USB and Bluetooth. The terminal in this deployment carries two RS232 channels, one of which is used for the scale. The remaining channel is available for a printer or a second peripheral. The MDT1065 provides dual RS232 and RS485, allowing the onboard scale and a label printer to run at the same time. The RS232 serial tablet interface page covers the device compatibility considerations for warehouse peripherals.

7. Outcome

The deployment was completed across the order picker fleet. The most direct change was the end of shift-end keying. Pick confirmations are written to the WMS as each line is completed, so the stock record reflects the racking at the moment of the pick rather than at the end of the shift. Inventory accuracy reports run at any point in the shift now show the actual state.

The second change was mid-shift re-sequencing. A revised pick order reaches the platform screen within seconds. The operator does not leave the aisle, and the machine does not return to the floor mid-sequence. The pick sequence follows the system in real time.

The third change was claims documentation. Damage photographs captured at the rack face are attached to the order line before the goods leave the pick area. When a claim arrives, the facility has an image of the case at the moment it was picked. The claims team resolves the question from the record rather than from correspondence with the customer.

8. Frequently Asked Questions