| Symptom | Likely Cause | Relation to 1829 |
|--------|--------------|------------------|
| PS081 (Subprogram not found) | Program number exists but search range exceeded | Direct – Increase 1829 |
| PS082 (External subprogram not found) | M198 fails due to buffer limits | Indirect – Also check I/O channel settings |
| Long delay before subprogram executes | 1829 set to 9999 in a memory with 5000 programs | Performance – Unnecessary scanning |
| Intermittent DNC failures | DNC buffer resets between blocks; search fails unpredictably | Systemic – Needs larger 1829 + stable handshaking |
Subject: Servo Alarm Detection Threshold (Excessive Error) System: FANUC Series 16i / 18i / 21i / 30i / 31i / 32i (and equivalent 0i models) Category: Servo Parameter (Axis-Specific)
The value for Parameter 1829 is generally set based on the maximum mechanical drift or servo hunting expected during a stop. FANUC recommends the following formula: fanuc parameter 1829
$$ \textParameter 1829 = \frac\textMaximum Allowable Drift\textDetection Unit $$
Typical Values (Example for a standard milling machine): | Symptom | Likely Cause | Relation to
Assume a linear axis with a travel range from -100.000 mm to +500.000 mm:
| Parameter | Setting (mm) | Purpose | |-----------|--------------|--------------------------------| | 1320 | -100000 | Negative software limit | | 1321 | +480000 | Positive soft limit 1 (warning)| | 1829 | +500000 | Positive soft limit 2 (final stop) | Values are stored in detection units (e
Values are stored in detection units (e.g., 1 μm → multiply mm by 1000).
FANUC Parameter 1829 is a critical axis-specific parameter used to define the "Excessive Error Detection Threshold" during a servo stop. It sets the limit for how far the machine axis is allowed to deviate from its commanded position while the axis is supposed to be stationary. If the actual position deviates from the target position by an amount exceeding the value set in Parameter 1829, the CNC triggers an alarm (typically Servo Alarm 410).
In modern high-mix, low-volume shops, programs are rarely stored entirely in CNC memory. Instead, operators drip-feed large files via DNC, or call subprograms from memory cards. Here, Parameter 1829 reveals its hidden danger:
Thus, Parameter 1829 is not a simple “enable/disable” switch—it’s a performance vs. reliability trade-off.