Need to connect Saia S-Bus and Modbus? The Weble WBox routes Saia S-Bus Modbus natively: one gateway speaks both protocols and maps data points in real time — no PC, no middleware, no cloud dependency.
The protocols
Saia S-Bus
Ether S-Bus is the native protocol of Saia-Burgess PCD controllers (SBC), widespread in Swiss buildings — reading and writing registers, flags, inputs and outputs.
Saia S-Bus driver →Modbus
Modbus (TCP/IP and RTU) connects PLCs, meters, variable-speed drives and countless industrial devices.
Modbus driver →Typical use case
A Saia PCD plant must exchange data with Modbus equipment — a third-party SCADA, frequency drives, a bank of energy meters. The WBox translates between the two worlds: S-Bus registers and flags appear as Modbus registers and coils, so the SCADA polls the legacy controllers without any change to the PG5 programs.
Example deployment
How the WBox bridges Saia S-Bus and Modbus
On one side the WBox is an Ether-S-Bus master, reading and writing PCD registers and flags over UDP 5050. On the other it serves or polls Modbus — RTU on RS-485 or TCP on Ethernet, as master or slave depending on your architecture. Each S-Bus point is mapped to a holding register or coil, with type conversion and scaling on the gateway. Bidirectional: SCADA writes land in the PCD, PCD states surface in the SCADA.
Capacity & limits
- Saia S-Bus — Ether S-Bus runs over UDP/IP — one connection per Saia PCD (station 0–255), reading and writing registers, flags, inputs and outputs; address lists import directly from PG5.
- Modbus — Modbus addresses up to 247 slaves per line (RTU or TCP) — about 32 RTU devices per RS-485 segment before a repeater.
On the WBox, a driver licence enables the whole protocol — there is no artificial per-point tier to unlock. Capacity scales with the gateway model, from the compact S103 to the E413: you are bounded by the field bus, not by your licence.
Frequently asked questions
How do I connect Saia S-Bus and Modbus?
Saia S-Bus is the Saia PCD controller protocol (Ether S-Bus) and Modbus is the industrial register-based protocol. A single WBox gateway runs the Saia S-Bus and Modbus drivers, speaks both protocols at once and maps the data points between them — no PC, no middleware, no cloud dependency.
Is the Saia S-Bus ⇄ Modbus bridge bidirectional?
Yes. The WBox reads and writes on both sides: a value or command on the Saia S-Bus side propagates to Modbus, and vice-versa.
Do I need a PC, a PLC or proprietary hardware?
No. The Saia S-Bus and Modbus drivers are licence-activated on one WBox — no gateway PC, no intermediate PLC and no proprietary hardware.
Which WBox model do I need?
Any WBox with the Saia S-Bus and Modbus driver licences. The online configurator recommends the right model from your interfaces and point count.
What you need
One WBox gateway with these two driver licences:
Route Saia S-Bus Modbus on your project
Find the right WBox gateway for your installation, or get in touch to validate your case.
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