PS116

Press SYSTEM key, navigate to PROGRAM display and identify the active macro program. Note the O-number and N-sequence number where alarm occurred.

Review the macro code at the alarm sequence. Check for assignments to system variables #3000-#3999 (macro interface), #4000-#4999 (PMC), #5000-#5999 (modal information which are read-only), or special constants #0, #1-#33.

Verify the Fanuc manual for your control series (0i/16i/18i/30i/31i/32i) section on macro variables. Confirm which variables in the #3000 series are writable versus read-only based on parameter 6031-6040 settings.

Modify macro program to use correct writable variable ranges: #100-#199 (common), #500-#999 (external), or correct writable #3001-#3032 PMC write range if parameter 6030#0=1 is enabled for PMC macro interface.

Changing system variable assignments may affect entire program logic - verify all macro variable usage before modification

Navigate to SYSTEM > PARAM screen, press soft key [SRCH] and search for parameter 6001. Verify bit settings - parameter 6001 should have appropriate bits enabled for macro executor type (Custom Macro B/C).

Search parameter 6030 bit 0 (WM1). If WM1=0, writing to PMC window variables #3001-#3032 is prohibited. Set parameter 6030#0=1 to enable write access if PMC interface variables are required.

Parameter modification requires parameter write enable (PWE) switch ON and may require machine restart - coordinate with production schedule

Check parameters 6031-6040 which define PMC address mapping for macro interface. Ensure correct address ranges are configured for the system variables being accessed in the macro program.

After parameter changes, cycle power to CNC (full power OFF/ON, not reset). Verify settings retained and test macro program in single block mode to confirm variable write operations complete without PS116 alarm.

Navigate to SYSTEM > DIAGNOSIS > [PARAM], then select diagnostic page for external I/O status (diagnostic 0300-0399 for Ethernet, 0700-0799 for serial). Monitor active communication attempts during alarm occurrence.

Check parameter 3290 (external data I/O protection) and parameters 8155-8159 (embedded Ethernet security). Verify external write permissions match intended access levels for connected devices.

Review external device program or communication protocol. Ensure write commands target only user macro variables (#100-#999 range) or specifically enabled external interface variables, not NC system variables (#5000+ which are read-only).

If using Focas/HSSB library functions, verify application uses appropriate write functions (cnc_wrpmacro for common variables, not system variable write attempts). Check return codes from Focas functions for access violation errors.

External device communication errors may affect automated production systems - test in manual mode before resuming automatic operation