Replacing SINUMERIK 810M GA3 with 802D SL on SIMODRIVE 611

1. Migration Context: Why Replace the 810M GA3

The SINUMERIK 810M GA3 (Siemens MLFB 6FC3551-1AC-Z, Software Version 3) is a compact three- to five-axis milling CNC that was widely deployed in the early 1990s on special-purpose machines including 5-axis diamond wire stone cutters. Field experience over the last decade shows that the controller is in a legacy/withdrawal phase: replacement CCU boards, lithium backup batteries, and the original 9" CRT/MDA monochrome operator panels are increasingly difficult to source, and the integrated 810 instruction-set PLC is no longer supported by current STEP 7 toolchains. The Operating Manual (SINUMERIK 810M GA3 Operating Manual, Software Version 3) and the Installation Guide (SINUMERIK 810/820 GA3 Installation Instructions, 01.93 Edition) remain the canonical reference for the legacy wiring, axis setpoint assignment, and commissioning sequence.

For a machine tool that still has mechanically sound SIMODRIVE 611 power modules, 1FK/1FT servo motors, and resolver or encoder feedback, the cost-effective path is a controller-only retrofit: keep the drive line intact and replace only the controller and operator panel. This article documents that path, focused on the SINUMERIK 802D SL plus the 4-axis ADI4 (Analog Drive Interface) module, the architecture that preserves the existing SIMODRIVE 611 hardware while delivering a modern HMI, contemporary PLC, and supported service lifetime.

2. Legacy Architecture Reference (810M GA3 + SIMODRIVE 611)

The 810M GA3 control is a self-contained CCU (Compact Control Unit) that integrates the NC kernel, the PLC, the HMI driver, and the I/O backplane on a single board. The 5-axis variant exposes the following interfaces relevant to a retrofit:

The SIMODRIVE 611 analog drives (6SN1 11x power modules with 6SN1 11x-xAx0x regulator cards, or modern 6SN1 12x equivalents) accept a ±10 V setpoint on terminal 56 (ref 14), encoder feedback on terminal XS1/XS2, and a 24 V enable on terminal 663 (ref 9). The 810M GA3 wired these directly, point-to-point, with shield grounds terminated at the drive cabinet ground bar. The 6SN1 118-xAA0x single-axis power modules (typically 8 A, 15 A, 25 A, 50 A, 80 A, 108 A, 160 A continuous) and the 6SN1 120/1 121-xAA0x two-axis modules (typically 2 × 8 A, 2 × 15 A, 2 × 25 A) are the most common in this machine class.

When the 810M GA3 is removed, the drive cabinet does not change: power modules, motors, resolvers, contactors, mains filter, line reactor, and the bus bar remain in place. Only the controller-side wiring harness, the operator panel, and the handwheel are replaced. The retrofit footprint in the cabinet is therefore small (a DIN-rail mounted CCU plus one or two ADI4 modules) and the machine downtime is dominated by the PLC program translation and the NC/PLC commissioning step, not by mechanical work.

3. Replacement Candidate Comparison

The candidates that have been considered for this class of retrofit, with their applicability for a 5-axis wire stone machine on SIMODRIVE 611, are summarized below.

Of these, the 802D SL plus ADI4 is the strategic choice when the SIMODRIVE 611 drive line is to be preserved. The 810D is technically excellent for this application but is no longer in production, leaving the operator dependent on service stock. The 828D and 840D sl are drive-line replacements, not controller-only retrofits, and represent a fundamentally different project (and budget).

4. SINUMERIK 802D SL Hardware Architecture

The 802D SL is a panel-mount CNC comprising three logical blocks:

1. CCU (Compact Control Unit) - hosts the NC kernel (up to 5 axes + spindle), the integrated PLC (S7-200-compatible), the PROFIBUS DP master, and the analog/digital I/O. Order codes are in the 6FC5370 family. The CCU is fanless and convection-cooled; it mounts on a DIN rail or backplate inside the cabinet.
2. PCU (Panel Control Unit) - the HMI front-end. Three variants are offered (see Section 6). The PCU is connected to the CCU via an internal HMI bus and is cut into the operator pendant face.
3. ADI4 (Analog Drive Interface for 4 axes) - an external PROFIBUS DP slave that converts four PROFIdrive slots to four ±10 V setpoint + enable pairs. Order code 6FC5 611-0DA01-0AA0 for the 4-axis variant and 6FC5 611-0DA02-0AA0 for the 2-axis variant.

The CCU exposes 4 high-speed digital inputs, 4 high-speed digital outputs, an Ethernet port, a USB port, a CF card slot, an RS-232 port, and the PROFIBUS DP master port. The PROFIBUS port connects to the ADI4 (and optionally to I/O blocks, a feed drive, or a SIMATIC ET 200 remote I/O). The CCU does not output ±10 V directly; the ADI4 handles that.

Typical cabinet layout for the retrofit:

• Controller cabinet: CCU mounted on the cabinet backplate, PCU cut into the operator pendant, ADI4 mounted on a DIN rail near the CCU, PROFIBUS cable linking CCU → ADI4 with PROFIBUS connectors and termination resistors.
• Drive cabinet (unchanged): SIMODRIVE 611 power modules and regulator cards, mains filter, line reactor, contactors, 24 V power supply. Only the setpoint wiring harness is re-terminated to the ADI4 instead of the 810 CCU.
• Operator pendant: PCU replaces the 9" CRT, the MDA keyboard is replaced by a USB keyboard plugged into the PCU (or eliminated if HMI softkeys suffice), the handwheel is wired to the CCU high-speed input.

5. ADI4 Module: Bridging 802D SL to SIMODRIVE 611

The ADI4 (Analog Drive Interface for 4 axes, MLFB 6FC5 611-0DA01-0AA0 for the 4-axis variant) is the keystone of the retrofit. It is a PROFIBUS DP slave with the following I/O per axis:

The ADI4 occupies one PROFIBUS DP node. The default PROFIBUS address is 3; the address is set with two rotary switches on the front of the module. For a 5-axis machine, two ADI4 modules are required (4 + 1 axis), or the 802D SL spindle output can be handled on the 4-axis ADI4 and the fifth NC axis can be implemented as a software axis on the second ADI4. The PROFIBUS address map is:

The ADI4 is configured in the 802D SL by adding a PROFIdrive slot in the NC configuration (SINUMERIK Commissioning Tool: Drive system → PROFIBUS nodes → Add → ADI4). The slot exposes 4 axis telegrams (standard telegram 3, PZD-5/9) plus a global status/telegram. The motor and encoder data are entered in the standard 802D SL axis configuration screen; the ADI4 is transparent for this purpose.

6. PCU Selection: Value, Pro, Plus

The 802D SL is offered with three PCU variants. The choice depends on the operator interface required, the NC program memory, and the HMI memory.

For a 5-axis diamond wire stone cutter with NC programs that may be several hundred KB (g-code, subprograms, compensation tables) and a tool table that scales with the diameter of the wire used, the PCU 70 Pro is the typical minimum and the PCU 70 Plus is the recommended choice. The Value variant is too small for the HMI screens typically required for wire speed, tension, and process visualization.

7. PLC Platform Migration: S7-200 vs S7-300

The 802D SL is built around an integrated S7-200-compatible PLC. The PLC program is written in LAD (Ladder Diagram) or FBD (Function Block Diagram) using STEP 7 Micro/WIN (Siemens' S7-200 tool) or the SINUMERIK-specific toolchain. The instruction set is smaller than the S7-300 used by the 810D and 840D - it does not include multi-instance FBs, SFBs, or the S7-300/400 STL language. Programs are downloaded to the 802D SL's internal flash over Ethernet or via the CF card slot.

By contrast, the 810D uses an external S7-300 PLC (CPU 314 or CPU 315) mounted in the cabinet and connected to the NC over PROFIBUS. Programming is in STEP 7 with the full S7-300 instruction set. Migration from a 810D PLC program to an 802D SL PLC program is therefore a manual translation: instructions, data blocks, and organization blocks must be rewritten in the S7-200 syntax. The wire stone machine typically has a moderate PLC program (50–200 networks), so this translation is a 1–3 day engineering effort rather than a full rewrite.

For the wire stone machine, the most common I/O is:

• Digital inputs: cycle start, cycle stop, feed hold, wire break detection, water flow switch, door interlock, emergency stop chain, handwheel pulses, reference switch per axis
• Digital outputs: spindle on, coolant valve, wire tension enable, tower lamp (red/amber/green), drive enable rail, lubrication pulse
• Analog inputs: wire tension feedback (0–10 V), water pressure (4–20 mA via 250 Ω shunt)
• Analog outputs: wire speed reference (0–10 V to a closed-loop wire drive), optional spindle speed override

For 4–6 digital inputs and 4 digital outputs, the 802D SL's onboard I/O is sufficient. Anything beyond that is brought in via an ET 200S on PROFIBUS DP (address 5 or higher). For analog I/O, an ET 200S with 2 AI / 2 AO modules is the typical choice, addressed as PROFIBUS node 5.

8. Remote Diagnostics and Connectivity

Remote service is a strong requirement for retrofits on machines located far from the OEM's service center. The 802D SL provides the following connectivity options out of the box:

For practical remote service, the recommended path is:

1. Connect the 802D SL Ethernet port to a 4G/DSL router on the customer site.
2. Establish a VPN tunnel from the service center to the customer router (WireGuard, OpenVPN, or IPsec).
3. Use a VNC or TeamViewer session into the HMI to operate the machine remotely, view alarms, and capture screenshots.
4. Use the SINUMERIK Commissioning Tool (Ethernet download) to update NC, PLC, and drive parameters.
5. Use the CF card or USB stick for off-line transport of large files (e.g., NC trace logs, compensation tables).

This connectivity set is comparable to the 810D's built-in modem option. The 802D SL's Ethernet capability, however, supports much higher bandwidth, allowing full HMI mirroring, file transfer at wire speed, and remote commissioning - all of which a V.34 modem cannot.

9. Mechanical and Electrical Migration Procedure

The retrofit is a phased migration. The drive cabinet is not powered down until the new controller is mounted and the wiring harness is ready to be re-terminated.

1. Pre-retrofit audit (machine powered, with HMI active). Record the following from the 810M GA3 HMI: NC version, PLC version, drive version, all machine data, all axis setpoint parameters, all compensation data (SSFK, pitch error, leadscrew error), all tool data, all part programs. Save to PG 675/PG 685 or via the service interface to a PC. Save the PLC program listing to paper if no electronic copy exists. Photograph the 810M GA3 terminal strip to capture the wiring assignment.
2. Order parts. Order the 802D SL kit (CCU + PCU 70 Pro or Plus), one or two ADI4 modules (4-axis and/or 2-axis variants), a CF card, and a USB-to-Ethernet adapter if needed for service laptop connection. Order the SIMODRIVE 611 documentation for the existing drive modules. Request a quotation through the Siemens Industry Mall with the machine's serial number, the existing 810M GA3 MLFB (6FC3551-1AC-Z), and the SIMODRIVE 611 module list.
3. Build the new controller cabinet (or sub-panel). Mount the CCU on a DIN rail or backplate, mount the PCU on the operator pendant cutout (or build a new pendant), mount the ADI4 on a DIN rail near the CCU, and lay out the PROFIBUS cable from CCU → ADI4 with PROFIBUS connectors and termination resistors. Wire the 24 V DC supply to the CCU, the PCU, and the ADI4 from a common 24 V power supply (typically 5–10 A for the controller section).
4. Pre-wire the new harness. On a bench, build the cable that connects the ADI4 setpoint outputs and enable outputs to the SIMODRIVE 611 regulator cards. Pin-out is documented in the 802D SL Commissioning Manual; the 611 regulator card terminal assignment is documented in the SIMODRIVE 611 Compendium. Use shielded twisted pair (e.g., LiYCY 2 × 0.34 mm²) for each setpoint pair, with the shield grounded at the drive cabinet end only.
5. Power down and re-terminate. Lock out the main disconnect, verify zero energy on the bus bars with a properly rated voltage tester, and remove the 810M GA3 CCU. Re-terminate the existing drive setpoint and enable wiring to the ADI4 terminals (not to the 810 CCU). Re-terminate the resolver/encoder feedback to the ADI4 encoder inputs. Re-terminate the handwheel to the CCU high-speed input. Keep the SIMODRIVE 611 modules, motors, mains filter, and contactors untouched.
6. Install the new operator pendant. Mount the PCU in the operator pendant cutout (a custom cutout may be required, sized for the PCU bezel). Wire the HMI bus from PCU to CCU with the supplied cable. Plug in a USB keyboard on the PCU (optional, useful for service).
7. Initial power-up of the controller section only. Energize the 24 V supply, the CCU, and the PCU. The PCU should boot into the 802D SL HMI. Verify the firmware version, NC version, and PLC version in the start-up screen. Apply the latest firmware from the Siemens support portal if commissioning tool reports a newer version.
8. Configure the PROFIBUS network. In the 802D SL Commissioning Tool, add the ADI4 nodes (one per ADI4) with the correct PROFIBUS addresses, assign them to the NC axes (X, Y, Z, A, C), and load the configuration to the 802D SL CCU.
9. Power up the drive section. Energize the SIMODRIVE 611 power supply. Verify the DC link voltage (typically 600 V DC for a 3-phase 400 V AC supply), verify no faults on the 611 modules, verify the enable chain.
10. Reference and verify each axis. Use the 802D SL HMI to home each axis individually. Verify direction (set MD32100 $MA_AX_MOTION_DIR), verify soft limits (MD36100 $MA_POS_LIMIT_MINUS, MD36110 $MA_POS_LIMIT_PLUS), verify the safety reduced speed (MD36030 $MA_STANDSTILL_POS_TOL).
11. Restore NC, PLC, and compensation data. Load the saved machine data, compensation data, tool data, and part programs into the 802D SL. Translate the PLC program from 810 instruction set to S7-200 LAD. Recompile and download.
12. Run a 5-axis test program. A 5-axis circular interpolation test (RTCP or non-RTCP) at low feedrate, then a high-feedrate dry run, then a full material cut. Verify wire tension, wire speed, and water flow interlocks.
13. Hand off to production. Document the new MLFBs, the PROFIBUS topology, the new IP address, the location of the PLC program source, and the location of the NC archives. Train the operator on the new HMI. Hand over the original 810M GA3 CCU and PCU to the customer for spare-parts inventory of the legacy cabinet, if other machines on site still use the 810 family.

10. Drive Commissioning on SIMODRIVE 611 with ADI4

Drive commissioning on the SIMODRIVE 611 is unchanged from the original 810M GA3 commissioning, with two differences: the setpoint source is now the ADI4 (instead of the 810 CCU), and the enable chain is wired through the ADI4. The key parameters are:

On the 802D SL side, the equivalent machine data for axis X are:

The procedure to commission a single axis is:

1. On the 802D SL HMI, navigate to Commissioning → Axes → [Axis Name] → Configuration.
2. Set the MD values above.
3. Save and reboot the NC.
4. Jog the axis in velocity mode at 5% rapid override. Verify the axis moves in the correct direction. If not, toggle MD32100 or swap two phases at the 611 regulator card (do not change motor phase wiring).
5. Jog the axis to a known position, mark the position. From the HMI, set the actual position (Commissioning → Axes → [Axis Name] → Set Actual Position). Drive to the reference switch; the axis should set the reference marker automatically.
6. Run a G0 back-and-forth test (e.g., G0 X-100 X0 X100) and verify the position readout matches the commanded position to within MD36030.
7. Run a circularity test (G02/G03) and check the contour deviation against MD36400.
8. Repeat for each axis (X, Y, Z, A, C) before any 5-axis test.

11. Verification and Acceptance Tests

Before handing the machine back to production, run the following acceptance tests. The results must be recorded and signed off by the commissioning engineer and the customer's production lead.

12. Troubleshooting Matrix

The following matrix captures the most common issues encountered on commissioning and the field fixes.

13. Spare Parts and Lifecycle Notes

For a 5-axis wire stone machine, the recommended spare parts inventory for the new control cabinet is:

The 802D SL is in active production as of the date of this document. Firmware is updated periodically; the Commissioning Tool will warn the operator when a new version is available. Always read the firmware release notes before applying an update: some firmware updates reset the NC machine data to defaults, requiring a re-commissioning. Recommended practice is to apply firmware updates during a planned maintenance window, with a verified backup of the current configuration.

Frequently Asked Questions