NETWORK / RTUEndpoint discovery
Finds RTU Unit IDs or confirmed TCP/TLS endpoints in a bounded subnet and reports network results as explicit IP:port pairs.
Discovery & diagnostics
Network and RTU discovery, Auto Scan, Protocol Diagnostics, Health, and Raw Traffic.
Discovery & diagnostics
Diagnostics observe the same native transaction stream as ordinary polling and writes. Start with the narrowest question; do not run an exhaustive scan when one known request can identify the fault.
AUTO SCANAuto Scan
Quick discovers practical readable ranges in all four address spaces. Exhaustive probes every single address and can issue 262,144 requests.
FC43 · MEI 0EDevice Info
Reads paged device identification and preserves standard and vendor-specific objects.
FC08 / 11 / 12 / 17 / 22Protocol Diagnostics
Runs safe specialist diagnostics, decodes returned fields, and retains attempts, latency and exact TX/RX frames. FC22 remains a confirmed write.
MEASUREConnection Health
Explains request lifecycle, latency distribution, throughput, retries, errors, connection state, and RTU utilization by source.
PROVERaw Traffic
Shows chronological frames, decoded fields, source attribution, timings, exceptions, filters, bounded recording, and export.
Choose Quick or Exhaustive scan
| Mode | Use when | Behavior | Cost / limitation |
|---|---|---|---|
| Quick | Unknown practical map | Adaptive block probes | May miss isolated readable addresses surrounded by illegal gaps |
| Exhaustive | Quick missed a known isolated address | Every address in all four spaces | Hours of traffic on a slow RTU link; use deliberately |
A diagnostic sequence that preserves evidence
Reduce the test
Stop unrelated views and reproduce with one address, one profile, and one expected value.
Check Health
Decide whether the failure is connection, timeout/retry, Modbus exception, malformed response, TLS, or CRC-related.
Open the transaction
Use Raw Traffic source attribution to inspect the exact request and response bytes.
Compare protocol fields
Verify Unit ID, function, PDU address, quantity, byte count, exception code, and timing.
Record a bounded artifact
Capture only the interval needed to reproduce. Export a session when another person must inspect it without the device.
Use Protocol Diagnostics deliberately
FC08 exposes safe serial-line diagnostic subfunctions, FC11/12 communication event state, FC17 server identification, and FC22 a masked holding-register write. Busloom excludes state-changing FC08 operations from this workbench. FC22 obeys the active profile's read-only policy and requires explicit write confirmation.