Configuring Sinumerik 802D Gear Stage Interlock for SIMODRIVE

1. System Overview and Scope

This procedure applies to a Betts Roll lathe equipped with a SINUMERIK 802D controller driving a SIMODRIVE 611 universal (611U) converter package. The spindle is a 55 kW AC induction motor controlled by a Yaskawa spindle drive amplifier section that is integrated into the 611U rack. The headstock has two mechanical gear stages selected by an electro-mechanical actuator, and the selection is sensed by two inductive proximity switches mounted on the gear-shifter fork.

The required interlock has the following behavior:

• Low gear (stage 1): 14–28 RPM, valid only when the low-range proximity switch is active.
• High gear (stage 2): 29–56 RPM, valid only when the high-range proximity switch is active.
• If a programmed spindle speed is inconsistent with the actual gear-stage sensor state, the controller must prevent the spindle from accelerating and must alarm the operator.

The implementation uses the SINUMERIK 802D built-in PLC to read the proximity switches, then writes the gear-stage state into the NCK/PLC interface bits V380x2000.0 and V380x2000.1. The NCK reads these bits to confirm the requested gear has been physically engaged before allowing spindle motion through MD35010.

2. Hardware Architecture

Refer to the SIMODRIVE 611 universal function manual (FBU) for the closed-loop speed control and positioning description: SIMODRIVE 611 universal Function Manual (FBU_0510_en.pdf).

3. Prerequisites

1. Sinumerik 802D controller with firmware that supports the 802D PLC toolbox (ToolsBox or PLC Programming Tool 802D).
2. SIMODRIVE 611U drive rack with the 55 kW power section commissioned and the 802D ↔ 611U bus link active (PROFIBUS or the integrated 802D drive bus, depending on the cabinet wiring).
3. Spindle motor encoder properly wired to the 611U measuring-system input (see FBU section 2).
4. Two inductive proximity switches, one per gear fork position, wired to free digital inputs on the 802D PLC (I0.0 / I0.1 are typically used; the 802D has 16 onboard DI).
5. Backup of the PLC program and NC machine data before any parameter change.

4. PLC/NCK Interface for Gear-Stage Feedback

On the 802D, the user data area between PLC and NCK is mapped into the V38000000–V380FFFFF range. The two specific bits of interest are:

Only one of the two bits is allowed to be TRUE at any time. The PLC must be debounced and the bits must be latched in a way that prevents both bits from being cleared during the shift transition (see section 7).

5. Machine Data Configuration

The gear-stage interlock is governed primarily by MD35010. For this two-stage application the following MD values are required:

Procedure to set MD35010 = 1 on the 802D:

1. Power the controller, reach the basic operator screen.
2. Press the Setup key, then enter the manufacturer password (default 802D commissioning password per site documentation).
3. Open Commissioning → Machine Data → Axis MD.
4. Locate MD35010, change from 0 to 1, accept with OK.
5. Cycle NCK power (or execute NCK reset) for the change to take effect.

6. Proximity Switch Wiring

Use a normally-open PNP inductive sensor rated for 24 V DC. Wire both sensors to the 802D PLC's onboard digital inputs through a screened cable, with the screen bonded at the cabinet end only.

Sensor 1 (low range)  → I0.0  (24 V, brown) / 0 V (blue) / signal (black) → I0.0
Sensor 2 (high range) → I0.1  (24 V, brown) / 0 V (blue) / signal (black) → I0.1

Typical wiring pattern:

• Brown: 24 V from 802D PLC sensor supply (e.g. terminal X2 pin 1).
• Blue: 0 V from 802D PLC sensor common (X2 pin 2).
• Black: signal to the 802D DI (X2 pin 3 for I0.0, X2 pin 4 for I0.1).

Confirm the input voltage at the 802D DI is > 11 V (high level) and < 5 V (low level) using the 802D diagnosis / status page. If the input is sitting at 8–10 V, check for voltage drop in long cable runs or a sinking sensor instead of PNP.

7. PLC Logic for Gear-Stage Selection

The 802D built-in PLC is programmed in the 802D programming tool (STEP 7 / WinCC flexible style STL or LAD). The logic below reads the debounced proximity-switch inputs and writes the appropriate bit into V380x2000.

7.1 Inputs and outputs (suggested allocation)

7.2 Debounce / latch segment (ST pseudocode)

// Debounce 100 ms on both prox signals
i_GearLow_D   : BOOL;
i_GearHigh_D  : BOOL;
TON_DebLow   (IN := i_GearLow,   PT := T#100ms, Q => i_GearLow_D);
TON_DebHigh  (IN := i_GearHigh,  PT := T#100ms, Q => i_GearHigh_D);

// Latch the active gear so V380x2000 never goes to 0,0 during shifting
IF i_GearLow_D AND NOT i_GearHigh_D THEN
    M_LatchedLow  := TRUE;
    M_LatchedHigh := FALSE;
END_IF;

IF i_GearHigh_D AND NOT i_GearLow_D THEN
    M_LatchedHigh := TRUE;
    M_LatchedLow  := FALSE;
END_IF;

// Mutually exclusive output bits to NCK
o_GearStage1 := M_LatchedLow;
o_GearStage2 := M_LatchedHigh;

// Mismatch detection: both prox active at the same time
o_GearFault := i_GearLow_D AND i_GearHigh_D;

7.3 Optional NC-side interlock

If your 802D application uses M40/M41-M42 for gear selection, the NC program (or the PLC interface) can verify the commanded speed against the actual stage. A simple rule on the PLC side:

// S analog (commanded speed) is mapped to V380x3000.0 (DWORD, RPM)
// Allow stage 1 if S <= 28, allow stage 2 if S >= 29 and <= 56
b_SpeedOK := (V380x3000 <= 28 AND M_LatchedLow) OR
             (V380x3000 >= 29 AND V380x3000 <= 56 AND M_LatchedHigh);

// Latch the spindle enable via M3/M4 path
b_SpindleEnable := b_SpeedOK AND b_M3OrM4 AND NOT o_GearFault;

Wire b_SpindleEnable into the drive enable path (interface bit V380x2001.0 or the equivalent drive-enable line for the 802D ↔ 611U link, depending on the firmware mapping). If the speed selection does not match the gear, the spindle will not receive an enable and the operator alarm "700020 Gear stage not permitted for programmed speed" is raised.

8. Verification and Commissioning

1. Manually shift the gear to LOW. Confirm V380x2000.0 = 1 and V380x2000.1 = 0 in the 802D diagnosis / status page.
2. Manually shift the gear to HIGH. Confirm V380x2000.0 = 0 and V380x2000.1 = 1.
3. Program a 20 RPM S-code, run M3. Spindle should start in low range, MD35110[0] = 28 caps the speed.
4. Program a 40 RPM S-code in low range. Spindle should fault / refuse enable because the requested speed exceeds MD35110[0] or the speed-mismatch interlock.
5. Program a 40 RPM S-code after shifting to high range. Spindle should accelerate to 40 RPM without alarm.
6. Block both prox signals (disconnect one at a time). Confirm o_GearFault goes true and the spindle does not run.
7. From the 802D service screen, watch MD35010, MD35090, and the active-gear stage. They must reflect V380x2000.

9. Troubleshooting Matrix

10. Extended Notes on the SIMODRIVE 611U Side

The 611U section must be commissioned before the gear-stage interlock can be tested at speed. Confirm the following from the 611U side:

• MD for the 611U spindle drive (e.g. MD1700 series on the 802D ↔ 611U link) match the 55 kW motor nameplate data.
• The external encoder is wired to the 611U measuring-system input, not the motor-mounted incremental encoder (the lathe uses the spindle-shaft encoder for actual speed feedback).
• Parameter assignment of the SIMODRIVE 611 universal board is per the SIMODRIVE 611 universal Function Manual (FBU_0510_en.pdf), section 3 "Parameterizing the Board".

If the 611U reports alarm 700055 (I/R module or monitoring module not ready), the gear-stage interlock cannot be reached because the drive itself is not enabled. Resolve the 611U alarm first, then re-test the spindle interlocking.

11. Field-Proven Caveats

• On 802D firmware versions below a certain level, the V380x2000.0 / V380x2000.1 bits may need to be re-asserted by the PLC every PLC cycle, not latched. Always hold the bit continuously (latch) and verify with a status viewer that the bit does not flicker.
• Inductive proximity sensors near the spindle can pick up electrical noise from the 611U chopper; use a 100 ms input debounce in the PLC, not just a hardware RC.
• Do not wire the prox sensors to 230 V relays that are also switched by the spindle contactor; the 802D PLC inputs are 24 V only.
• When MD35010 = 1, the 802D expects a valid gear-stage feedback within the first spindle enable after NCK reset. If the gear is mid-shift during NCK boot, the alarm will appear until the shift completes. Train operators to power up in a known gear position.
• The 55 kW motor's thermal model in the 611U uses the active gear stage to scale the thermal time constant. An incorrect gear-stage bit can lead to premature or delayed thermal trips; the interlock also protects the motor thermally.

12. Acceptance Test Checklist

1. MD35010 = 1 verified on the 802D machine-data display.
2. MD35090 = 2, MD35110[0] = 28, MD35110[1] = 56 confirmed.
3. Proximity switches wired per the schematic and the input state page shows clean 0/1 transitions.
4. V380x2000.0/0.1 latches correctly with no transient 0,0 state.
5. Low-range S-code (e.g. S=20 M3) starts the spindle without alarm.
6. High-range S-code (e.g. S=40 M3) starts the spindle without alarm.
7. Mismatched S-code (S=40 in low range) refuses spindle enable and raises the operator alarm.
8. Alarm 700055 and any 611U drive alarms are clear before commissioning sign-off.

Frequently Asked Questions