FANUC 30i/31i/32i-B: a read-only check of FSSB connection status

When servo communication fails, guessing which drive is faulty from its cabinet position can confuse communication-line order with machine axis names. Save FSSB connection status and compare it with the original wiring documents to distinguish what the system recognizes from what is physically installed.

Applicable systems and screen access

Based on B-64485EN/01, this example covers the manual’s 30i-B, 31i-B/B5 and 32i-B systems. Under SYSTEM, advance through the continuing menus, select FSSB and then connection status. The manual describes this screen as showing slaves detected at power-on, including FSSB line numbers, slave types and axis-related information. It is an identification result, not a comprehensive health assessment of every component.

Record the line–slave–axis relationships

1. Photograph the full screen and record the current alarm and time. Save each line separately when several exist; do not capture only the last row.
2. Copy each row’s line number, slave number, displayed type and axis name into a table. Keep the original numbering instead of rearranging it to suit personal habits.
3. Match these records with the machine’s original wiring diagram, earlier normal-state screenshots and component labels. Similar-looking amplifiers cannot be assumed to have identical specifications merely from their positions.
4. List the differences: which rows remain visible, which are missing, whether axis names match historical records, and whether optical cables or components were moved or replaced before the fault.

A field table can use five columns: screen row, cabinet label, complete specification, historical status and current status. If no historical information exists, record the present state and mark “no normal-state reference yet”; do not enter a guessed order as the original configuration.

Do not rush into automatic setting when a difference appears

A connection-status discrepancy warrants further checks, but this page alone cannot distinguish power, connection, device-specification and configuration factors. The FSSB menu also contains setting functions. Until the machine configuration, original parameters and backups are confirmed, do not run automatic setting or write data merely to make the list look orderly. Otherwise, later investigation may not distinguish the original fault from changes introduced during troubleshooting.

Using the record for the next repair step

Provide repair personnel with the complete alarm, every connection-status page, an overall cabinet photograph and relevant nameplates, plus a timeline of recent actions. Opening the cabinet, disconnecting optical cables or replacing parts requires appropriately competent personnel following equipment maintenance procedures. This preparation guide stops at read-only observation. If SV5136 (Chinese) also occurs, continue diagnosis using the applicable alarm manual. Further material is in the FANUC section.

References and applicability

• FANUC Series 30i/31i/32i-MODEL B Maintenance Manual B-64485EN/01 (public mirror of the manufacturer’s manual): §8.2, printed pages 489–490.