Definition
In the "Yard Management and Gantry Crane Data" scenario, sensors and business terminals often access platforms via cellular IoT; coverage quality, latency, security, and the full lifecycle of card services must all be considered.
Technical Features
It is recommended to differentiate telemetry, alarms, configuration, and OTA traffic; configure caching and retransmission in weak network environments; include TLS, certificates, and keys in the change and rollback strategy.
Use Cases
Applicable to distributed sites and remote operations. SimtoLink can provide combined capabilities like connection management, data pool, and directed/private networks, supporting large-scale replication.
Key points for cooperation with IoT SIM cards
- Ledger: ICCID / IMEI bound to device number, installation location, and person in charge.
- Network: APN, whitelist, SIM-device binding, and regional/roaming policies.
- Operations & Maintenance: online rate, abnormal traffic, silent SIMs, and alert closure in ITSM.
- Compliance: log desensitization, retention period, and cross-border/subcontracting agreements.
How the slot, the reshuffle plan, and the spreader cycle line up
Yard management watches three things at once: which bay, row, and tier a container occupies now, where the boxes above it will be moved so a lower box can be taken out, and how long the gantry crane took to pick, travel, and set down. What the IoT SIM returns is a measurement from the spreader and the crane, not the plan itself. The plan is in the dispatch system. The measurement is on the crane. They line up on the job id: this move, which container, from which cell to which cell. Weight without a job id cannot be filed. Position without lock state makes the system write the coordinates while the spreader is still in the air as the new slot.
A complete move includes the job id, the container number, the start cell, the target cell, the lock time, the unlock time, the spreader weight, and the crane id. The cycle is the interval from one lock to the next lock. That is closer to real capacity than "how long the equipment was online." An intermediate set-down from a reshuffle is also a slot change. Skipping the intermediate cell makes inventory show one container in two places, or briefly in none. If an inland yard and a port terminal share container numbers, the position has to carry the yard code. Otherwise a bay of the same name is written into the other yard.
A local queue backfills the uplink while the gantry travels
A gantry crane moves along the rail, and the signal rises and falls as it passes steel and container stacks. Cellular return is usable only if the terminal in the cab or the electrical cabinet can store hook events in order while the link is down, and send them with the original time after it attaches again. Sampling only the "current coordinates" when the network is up makes a set-down during the outage disappear. The antenna belongs outside the structure, away from the spreader cable's repeated bend. Inside a steel box girder, a stationary test may have signal and travel then loses it. The terminal clock has to match the dispatch system. An old event backfilled as if it just happened writes a slot that was already updated back again.
Video, remote desktop, and hook events should not share one priority. When a session that is watching the picture fills the channel, the lock signal cannot get out, and dispatch keeps waiting on the plan. When weight is used to check a wrong box or an overload, take it after lock and after the hoist has settled. The shock reading at the start of the hoist cannot be used directly as the container weight. When TOS exists as well, agree which side is the source of the set-down confirmation. If both sides can write the slot, a backfill that arrives later covers a correct position that arrived first. The crane id and the SIM identity should stay bound. A spare terminal put in place that keeps the old binding records hook data against the crane that is already out of service.
A container number that does not match, and a slot written before the twistlock
When the container number from optical recognition does not match the number on the dispatch order, updating the slot from the order anyway puts the box that was actually lifted into the wrong cell in the system. This should stop at pending confirmation, not close automatically. If a driver edits the number by hand and the original recognition is not kept, it is impossible later to tell a recognition error from a wrong order. Uploading the target cell before the lock, then changing the move mid-hoist, makes inventory show the box already in the new position while it is still on the spreader. The next move is sent to that "occupied" cell, or sent to pick a box that is still in the air.
A reshuffle left half done at shift change leaves the intermediate slots only in the driver's memory. The system still has the layout from before the job started. The handover should list job ids that are not closed, rather than only whether the equipment is online. Zero drift on the scale makes an empty spreader show a stretch of weight. If that is used to decide "there is a box on the spreader," moving an empty crane also rewrites slots. If FMS is responsible for when the truck reaches the yard, truck arrival and spreader lock are still two events. Using the truck's entry time as the set-down time puts the slot earlier than the real move. Gantry anti-collision and position calibration are safety functions on the crane itself. A cellular report does not replace local protection on the crane.
When the same container number has two target cells in a short time, keep both job ids for the shift to check. Do not keep only the last one by arrival time. After an overwrite, the covered move cannot be reconstructed from inventory. If weight and container number come from different terminals, both have to use the same job id. Pairing only by close timestamps crosses the weight of two neighboring moves onto each other's boxes. When a gantry spans two blocks, the bay has to carry the block code. Otherwise an east-block bay is written as an empty cell in the west block. After a spare SIM or a spare terminal is brought into service, run one lock test and confirm the event reaches dispatch before accepting a live job.