SIMOTION D445 Drive Enable: Resolving Power Enable and OFF2/OFF3 Disabled States

A SIMOTION D445-2 DP/PN controller (order number 6AU1445-2AD00-0AA0) running on SIMOTION Scout 4.4.0.6 HF6 can present a confusing condition in which the integrated SINAMICS S120 drives report all enable signals as disabled: Power Enable, Drive Enable, OFF2, and OFF3 all evaluate as inactive even though no alarm is active, the module LEDs are green, and the infeed is running. The most common cause is a CF card whose contents were either wiped, partially overwritten, or replaced with a copy from another machine. This article documents the drive-enable signal chain in SIMOTION D, the root cause of the disabled state after CF manipulation, the re-commissioning procedure using Scout, the parameter and control-word bits that must be in the correct state, and the emergency path when no backup exists.

1. Drive Enable Signal Chain in SIMOTION D

SIMOTION D is a motion controller with an integrated SINAMICS S120 CU320 control unit. Drive enables are not simple binary signals — they form a bit-mapped control word (STW1) sent from the SIMOTION TO axis to the SINAMICS drive object (DO), with status feedback in ZSW1. The five user-visible enable lines (Power Enable, Drive Enable, OFF2, OFF3, Pulse Enable) are derived from these control word bits and from configured BICO interconnections on the SINAMICS side.

The user-visible Power Enable, Drive Enable, OFF2, and OFF3 fields in Scout map to the following:

• Power Enable → STW1 bit 0 (ON/OFF1) sourced from the TO axis. Required for ramp-up.
• Drive Enable → STW1 bit 3 (Enable inverter / pulse enable). Required for torque-producing output.
• OFF2 → STW1 bit 1. Must be 1 (inactive) to run. 0 = coast to stop.
• OFF3 → STW1 bit 2. Must be 1 (inactive) to run. 0 = quick stop.

If any of these four is 0, the SINAMICS state machine sits in either Switching On Inhibited (ZSW1.6 = 1) or Ready to Switch On (ZSW1.0 = 1) and the motor will not move. The control panel will refuse to run the axis.

2. Symptom: All Four Enables Disabled After CF Card Wipe

The reported condition — Power Enable = disabled, Drive Enable = disabled, OFF2 = disabled, OFF3 = disabled, no alarm, green LEDs, control panel cannot enable — has a specific root cause on the SINAMICS side: the BICO interconnections for OFF2, OFF3, and Pulse Enable are missing. These interconnections live in the SINAMICS drive's parameter image on the CF card. When the CF is wiped, reloaded, or restored from a different machine, the SINAMICS parameter set on the boot partition may be missing or the BICO sources may not point to the PROFIdrive telegram bit (e.g., r2090.1 for OFF2, r2090.2 for OFF3, r2090.3 for pulse enable). The drive therefore powers up with all enable sources de-asserted.

Additional indicators of this specific failure mode:

• Module LEDs (RDY, DC LINK, COM) are green on Motor Modules and Infeed.
• SIMOTION D445 status LEDs: RUN green, STOP off, SF off, BF off.
• No entry in the SINAMICS diagnostic buffer (r0945 / r0947).
• No entry in the SIMOTION diagnostic buffer.
• Control panel axis enable command is rejected; no fault message appears, simply "command cannot be executed".

3. Root Cause Analysis Workflow

Use the following ordered checks to confirm the diagnosis before re-commissioning:

1. Open Scout, go online with the D445, and expand the SINAMICS drive in the project tree.
2. Right-click the drive DO → Diagnostics → Status / Control Word. Verify ZSW1 bit pattern: ZSW1 = 0x0641 indicates Switching On Inhibited (bit 6 + bit 10 + Ready_to_switch_on pattern).
3. Open the parameter list and inspect p0844[0] (OFF2 source), p0848[0] (OFF3 source), p0852[0] (Pulse enable source), p0864[0] (Infeed operation source). All four should be interconnected to the corresponding PROFIdrive control word bit, typically r2090.1, r2090.2, r2090.3.
4. If any of these BICO sources is 0 or points to a constant 0 signal, the enable chain is broken.
5. Cross-check r46 (ZSW1) and r47 (ZSW2) to see the live status word. In Control Panel mode, also check r898 (active STW1).

4. Re-Commissioning Procedure (CF Card Has Project Backup)

If the Scout project archive exists, the cleanest recovery is to reload the project and re-download to the D445. This restores both the SIMOTION runtime and the SINAMICS parameter image, including all BICO interconnections.

4.1 Prerequisites

• Scout 4.4.0.6 HF6 installed (or the version matching the machine archive).
• Project archive *.zip or *.srt from the machine's CF card backup.
• Ethernet cable between the engineering PG/PC and the D445 X127 service port (or X150 PROFINET port, depending on topology).
• PG/PC IP set to a free address in the same subnet as the D445 (default 169.254.11.22 for X127 service interface).

4.2 Step-by-Step Reload

1. Extract the project archive to a working folder. Open the *.srt in Scout via Project → Open.
2. Set the PG/PC interface to the Ethernet adapter connected to the D445 (Options → Set PG/PC Interface → TCP/IP).
3. Select the SIMOTION D445 in the project tree and click Download (or right-click → Download to target system → CPU and SINAMICS). This transfers the SIMOTION runtime and the SINAMICS drive configuration (including BICO) in a single step.
4. Wait for the download to complete. The D445 performs a restart; the SINAMICS CU320 reloads its parameter set from the download.
5. Go online (Online → Connect to target system). Right-click the D445 → Commissioning → Assign IP address if the device shows up under Accessible nodes but is not bound to the project IP.
6. Expand the SINAMICS subtree, right-click each drive → Commissioning → Automatic commissioning and click Start if the wizard prompts for re-commissioning. The automatic wizard re-validates motor identification data, encoder configuration, and the BICO chain.
7. After the automatic commissioning finishes, check the parameter list: p0840, p0844, p0848, p0852 should now be interconnected to r2090.x.
8. Open the Control Panel on the TO axis. Enable the axis. The ZSW1 bits should toggle to Operation Enabled (ZSW1.2 = 1). If enabled, jog the motor at low speed to verify the drive follows setpoint.

4.3 Verification

5. Re-Commissioning From Scratch (No Project Archive)

If the project archive was on the lost CF card and no other backup exists, the commissioning must be rebuilt manually. The D445 can boot from a blank CF card and present itself on the PROFINET/DriveBusCliQ network as an unconfigured node. The procedure follows.

5.1 Project Creation

1. Scout → File → New Project. Insert a SIMOTION D445-2 DP/PN device from the catalog at order number 6AU1445-2AD00-0AA0.
2. Open HWConfig. Drag the SINAMICS S120 infeed (e.g., 6SL3130-6TE21-6AA4 for Active Line Module 16 kW) and the Motor Modules (e.g., 6SL3120-2TE21-8AA4 for 18 A Double Motor Module) into the DRIVE-CLiQ slots. Match the slot numbers to the physical wiring exactly — DRIVE-CLiQ topology is order-sensitive.
3. Configure the PROFINET interface: assign IP, subnet mask, and PROFINET device name. The default name format is d445pn.
4. Save and download the hardware configuration. The D445 will now know about the drive topology.

5.2 Automatic SINAMICS Commissioning

1. Go online. Right-click the SINAMICS subtree → Commissioning → Automatic commissioning.
2. The wizard reads each Motor Module's electronic nameplate (motor type, encoder, current limit) from the DRIVE-CLiQ connection.
3. Select the power unit and motor from the detected list. Confirm encoder type and resolution.
4. Set the mains voltage, infeed type, and cooling method. Accept the default for standard Active Line Modules (400 V, 50 Hz, air-cooled).
5. The wizard performs motor data identification (p1910) and encoder calibration (p1990) when triggered. These tests require the motor to be free to rotate; ensure safety clearances.
6. After completion, the BICO interconnections p0840, p0844, p0848, p0852 are set to their factory defaults pointing at r2090.x. The enables should now function.

5.3 Technological Object Axis Configuration

1. Right-click Technological Objects → Insert New Object → Axis → Electric Axis (TO / Axis). Create one TO per drive.
2. In the axis configuration wizard, assign the drive (DO number from HWConfig) to the TO.
3. Configure the mechanical system: load gear ratio, position tracking, software limit switches.
4. Configure the encoder: assign the encoder from the SINAMICS drive (typically encoder 1 on the Motor Module).
5. Set the velocity profile: maximum velocity, acceleration, jerk limit. For commissioning, use a conservative profile (e.g., 100 mm/s, 1 m/s²).
6. Compile the configuration and download.

5.4 User Program Structure

The minimum MCC or ST program to enable an axis named Axis1:

// Structured Text - Axis Enable Pattern
PROGRAM AxisControl
VAR
    bEnable : BOOL;       // Hardware enable input
    bPowerOn : BOOL;      // Operator power-on request
    bReset : BOOL;        // Fault reset request
END_VAR

IF bEnable AND bPowerOn THEN
    Axis1.Enable := TRUE;
    Axis1.OperatingMode := OPERATING_MODE_POSITIONING;
ELSE
    Axis1.Enable := FALSE;
END_IF;

IF bReset THEN
    Axis1.CommandBuffer.Command := 'RESET';
    Axis1.CommandBuffer.Execute := TRUE;
END_IF;
END_PROGRAM

For the full MCC flow, use the Axis Enable and Power function blocks from the Motion library. The MCC editor auto-generates the equivalent ST when the Generate ST source option is used.

6. CF Card Source Matching and IP Collision Avoidance

If the lost CF is replaced by a copy of another machine's CF card, the SIMOTION runtime and SINAMICS parameter set load correctly, but two side effects must be managed:

1. PROFINET IP collision — the copied CF carries the source machine's IP and device name. If both machines are powered on the same network, PROFINET communication will fail. After copying, immediately change the IP and PROFINET name in Scout to match the target machine's network plan.
2. License dongle — SIMOTION runtime licenses are machine-specific. The CF copy does not transfer license keys; if the target machine uses optional function packages, re-install the license via the Scout license manager (Options → License Management).
3. Drive object numbers — DO numbers in the SINAMICS configuration are assigned during HWConfig download. If the source and target machines have different Motor Module counts, the DO numbering may not match the physical DRIVE-CLiQ topology. Re-do HWConfig on the target.

7. LED Diagnostics Reference

In the reported case, the LEDs were all green — which confirms that the SINAMICS hardware and DRIVE-CLiQ links are healthy, narrowing the fault to the enable logic layer, not the power stage.

8. Parameter Table for Enable Restoration

When re-commissioning manually, the following SINAMICS parameters govern the enable chain. All values are factory defaults unless noted. BICO source format: biCoParameter.bitNumber.

The key observation: when the factory default is 1 (constant true), the drive is always enabled as long as the OFF2/OFF3 lines are 1. When wired to r2090.x, the enable is PLC-controlled and follows the TO axis enable output. A wipe of the CF card resets these to 0 in some firmware versions, which is why all four enables appear disabled.

9. Emergency Commissioning Without Any Backup

If the project archive is lost and the CF card is damaged beyond recovery, the SIMOTION D445 can be restored to a usable state by the following procedure. The hardware configuration of the SINAMICS drives can be uploaded from the running device, but the user program cannot be recovered without a backup.

1. Insert a new, blank CF card into the D445. The D445 will boot into a service state and present itself on the service interface (X127) with default IP 169.254.11.22 (or the address stored in the device, if any).
2. Configure the PG/PC to a compatible IP (e.g., 169.254.11.10). Open Scout → Online → Accessible Nodes. The D445 should appear in the list.
3. Right-click the accessible node → Upload to PG/PC. Scout reads the device configuration and creates a new project with the actual hardware topology. This step does not recover the user program, but it does recover the SINAMICS parameter set.
4. Save the uploaded project. Verify the SINAMICS drive parameters and BICO interconnections — these come directly from the device, so they should be intact.
5. Test the drive via Control Panel. If the drive enables and runs, the enable chain is healthy.
6. Recreate the user program from documentation. SIMOTION MCC or ST source files are project-specific and cannot be reconstructed automatically. If the original MCC charts are gone, the application must be rewritten from the machine's functional specification.
7. For the case where the device shows up with default factory firmware settings (no prior project), the BICO sources will all be 1 (constant true) and the drive will respond to hardware enable signals (terminal EP at the Control Unit). In this mode, drives can be jogged via the S120 Starter tool connected to the X127 service port, bypassing SIMOTION entirely.

10. Verification Checklist

Run these checks in order after re-commissioning. If any check fails, return to the corresponding section.

11. Troubleshooting Matrix for Common Enable Failures

12. Summary

The four-line enable state in Scout (Power Enable, Drive Enable, OFF2, OFF3) is a user-friendly view of the SINAMICS STW1 control word. When all four appear disabled without an active alarm, the cause is almost always a missing or rewired BICO interconnection on the SINAMICS side, typically resulting from a CF card wipe, replacement, or restoration from a different machine. The recovery path is: (1) restore the project archive via Scout download to repopulate the SINAMICS parameter set, (2) run automatic commissioning to validate motor and encoder data, (3) verify BICO sources p0840, p0844, p0848, p0852 point at the expected r2090.x PROFIdrive bits, and (4) test the drive via the TO axis Control Panel. When no project backup exists, the D445 can be uploaded from the device, but the user program must be recreated from documentation.