SYST-018

Verify current robot position matches program line

Press POSN on the teach pendant and verify the current TCP position. Compare this to the expected position at the selected program line. Check all six axes on the Joint or XYZ display to ensure alignment.

Starting from an incorrect position can cause collisions, especially with lines containing linear or circular motion commands that assume a specific starting point.

Review I/O and peripheral states

Navigate to MENU > I/O > Digital to check all tool, gripper, and fixture outputs. Verify these match the expected states for the selected start line. Check welding/spot gun states, conveyor tracking status, and any vision system flags.

Create a manual I/O checklist for common restart points in critical programs. Many production issues stem from gripper state mismatches when restarting mid-program.

Verify payload and tool frame settings

Check MENU > SETUP > Frames to confirm the active UTOOL and UFRAME match what the program expects at the restart line. Review any PAYLOAD commands executed before the selected line that may not be active.

Lines with dynamic payload changes or tool changes are particularly risky restart points. Consider using PROG_UFRAME and reading current tool/frame registers before continuing.

Check program registers and position registers

Navigate to DATA > Registers (R[]) and Position Registers (PR[]) to verify critical values. Check any registers used for counters, calculations, or conditional logic between the stopped line and restart line.

Skipping initialization routines can leave registers at unexpected values, causing logic errors or motion to incorrect positions stored in PRs.

Acknowledge alarm and test in single step mode

Press RESET to clear the warning, then set the teach pendant to STEP mode. Execute one line at a time while monitoring motion path and I/O states. If safe, switch to low override (5-10%) before continuous execution.

After acknowledging SYST-018, the first motion command is the highest risk. Always verify it in STEP mode before committing to full-speed execution.

Identify the original stop position

Check the production log or program history to determine where execution actually stopped. Navigate to MENU > ALARM > Log (F1) to review recent alarms and the program line numbers associated with previous stops or errors.

Enable $SCR.$PROG_TRACE in system variable $SCR_CFG to log detailed program execution history including line numbers and timestamps.

Return cursor to correct program line

Use the teach pendant arrow keys or FIND function (FCTN > Find) to navigate back to the correct line number. Look for the line marker indicator (>) on the left side of the program display showing the execution pointer.

Do not press SHIFT+RESET which resets the program to line 1. Use only cursor navigation to return to the stopped position.

Verify no program edits occurred during cursor movement

Check if the program was modified while the cursor was moved. Press SELECT to view program details and check the last modified timestamp. If edited, reload the original from backup via MENU > FILE > Open.

Enable edit protection using controlled start (RMT/EXT mode requirements) to prevent accidental program changes during production. Set $SCR.$CSTOP_EN = 1 and configure appropriate I/O signals.

Reset alarm and continue from correct position

Once the cursor is at the correct stopped line, press RESET to clear SYST-018. Verify the line number displayed matches the intended restart point. Press cycle start to continue normal execution.

Train operators to use the HOLD pendant button instead of PAUSE when reviewing code during execution, as this prevents inadvertent cursor position changes.

Check Karel or macro background logic programs

Navigate to MENU > STATUS > Program Select and check if any background logic (BG Logic) programs are running. Press F1 [TYPE] to view all active tasks including macros that may have issued program reset or line select commands.

Review Karel programs for RUN_TASK, SET_LINE, and PROG_JPOS commands that can alter program execution position. Check macro variable $MNUTOOLNUM and $MNUFRAMENUM for frame changes.

Verify PLC program control signals

Check the PLC interface signals controlling program selection and execution. Navigate to MENU > I/O > PLC to review UI signals (User Interface). Look for program select signals (typically UOP[1-8]) and program reset commands that may have triggered the position change.

Misconfigured PLC interlocks can repeatedly reset program position, creating a cycle of SYST-018 alarms. Verify PLC logic before continuing.

Review system variable changes

Check $SHELL_CFG, $RMT_MASTER, and $TP_CTRL system variables for external control configuration. Navigate to MENU > DATA > System Variables and search for $PROG_SEL to see if external program selection is active.

Set $SCR.$SHELL_WRN = 1 to generate additional warnings when external devices attempt to control program execution, helping diagnose integration issues.

Verify host communication and Ethernet protocols

If using PC interface, PCDK, or socket messaging, check MENU > SETUP > Host Comm for active connections. Review $HOSTCOM system variables and check if remote program control is enabled with inappropriate permissions.

Implement proper user authentication via MENU > SYSTEM > Security to restrict program control permissions. Use password-protected application accounts for external devices to prevent unauthorized program repositioning.