Scope and preparation

Use the affected SB1000's web interface. Commissioning mode is available in firmware 6 and later; listen-before-transmitting behavior was added in firmware 7 and Register scan in firmware 8. Check the installed version and its visible tools.

Commissioning takes over both serial ports and suspends their normal operation. Arrange the interruption before entering it. Identify the existing bus master and the expected field devices, addresses, and serial settings. Save a configuration backup when appropriate.

1. Prepare the bus

1. Check power, data-pair wiring, signal reference, topology, end termination, and bias against the equipment documentation.
2. Confirm one deliberate master arrangement. Do not connect SB1000 as another independent transmitting master on an active RTU bus.
3. Enter commissioning and inspect the line settings for each port.
4. Keep listen-before-transmitting enabled when available. If it reports a busy bus, identify the traffic and isolate the segment appropriately before proceeding.

2. Search a deliberate range

Start with the known baud/parity and expected address range. Broad searches take longer and may find ambiguous responses. Choose a probe function/register documented for the device when a generic probe produces no answer.

A Modbus exception still shows that a device answered. An empty result is not proof that no equipment is present: the probe, address range, serial settings, or wiring may be wrong.

The optional “Also try swapped A/B polarity” pass is experimental and does not work with all equipment. If an address responds only that way, check and correct its data-line wiring, then repeat a normal scan. The temporary inversion is not a permanent repair.

3. Interpret the result

• OK: a response was detected under the tested conditions. Verify actual points before accepting the installation.
• Wrong parity: the UART observed parity/framing errors. Use the documented settings and verify a clean read.
• Conflict: repeated corrupted replies can indicate duplicate addresses, but wrong settings and other faults can look similar. Isolate suspected devices and retest.
• Garbled: a corrupted response was heard but did not repeat consistently. Check settings, noise, late replies, and competing traffic.
• A/B swapped: the optional inverted test found a response. Correct the physical data wiring and verify with normal polarity.
• Multiple stop-bit matches: the reply does not reliably reveal the stop-bit setting. Use the manufacturer's value.

4. Verify the points

Add the intended devices to the list and select the correct library solution or custom definition for the exact model. A library entry is a starting definition, not proof that the connected equipment matches it.

Read a documented point and compare with the field display. Check table/function, zero-based offset, width, signedness, order, scale, units, and invalid-value codes. A register scan offers alternative interpretations; several plausible numbers do not tell you automatically which one is correct.

On firmware with Register scan, restrict the range and use paired reads when required by devices that expose only complete 32-bit values. Export the results if they help document an unresolved map issue.

Perform writes only as a planned, reversible test. Read feedback and restore or release overrides afterward. A write acknowledgement alone does not prove physical movement.

5. Return to normal service

1. Save or print the commissioning report and note unresolved findings.
2. Apply the required normal serial settings. A scan can temporarily use other settings and restore the configured values when it ends.
3. Finish test overrides, then exit commissioning.
4. Reconnect through the production network if the commissioning hotspot closes.
5. Verify the intended port modes, TCP ports or MQTT/BACnet configuration, and one correct live value in the external system.

Keep the report together with the firmware version, wiring/address list, and point definitions. A successful scan becomes a completed integration only after normal operation has also been verified.