Build a read plan
Views, ranges, custom addresses, polling, and optimization.
Build a read plan
A view is a subscription to one Modbus address space. It owns an address selection and poll interval. The native scheduler—not a browser timer—turns that selection into FC01/02/03/04 requests, retains raw history, and publishes bounded UI updates.
Choose the address selection
| View type | Use when | You define | Trade-off |
|---|---|---|---|
| Contiguous range | The device map is dense | Start address + count | Simple and efficient when every address in the block is readable |
| Custom addresses | The map has holes or sparse tags | Explicit address list | Busloom groups safe adjacent addresses and avoids unreadable gaps |
| Auto Scan result | The map is unknown | Discovered readable range | Good starting point; refine it after learning the actual device |
Create and validate a view
Pick the address space
Coils, Discrete inputs, Holding registers, and Input registers use different function codes and cannot share one view.
Select addresses
Enter a range or custom set. Include every continuation word required by multi-register tags.
Inspect Read Plan
Review exact blocks, function codes, gaps, continuation words, and estimated frame sizes before polling.
Set a realistic interval
Choose an interval the device and link can sustain. Fast UI refresh does not create faster polling.
Start the source
Use the floating bar. Running, stopped, waiting, and error states describe acquisition—not connection state.
Verify timestamps and frames
At least two successful cycles should update timestamps and produce matching traffic before you build dependent Trends or automation.
When polling is too slow
- Check Connection Health for actual latency, retries, and RTU utilization before reducing the interval.
- Prefer coherent blocks over many isolated addresses when the device accepts the intervening range.
- Do not include known illegal gaps merely to create one visually neat range.
- Remember that automation temporarily owns the connection and may interrupt background requests.