Sinumerik 810T GA1 Handwheel Installation and Parameter Setup

Overview

The Sinumerik 810T GA1 is a two-axis (X, Z) CNC for turning centers that was shipped with an integrated PLC (typically a SIMATIC S5-130WB or compatible submodule) and a fixed operator panel. Manual axis jogging through a handwheel (electronic handwheel, pulse generator, or "Handrad") is supported natively, but the control does not auto-detect the encoder — the handwheel channel must be enabled in machine data, wired through the I/O submodule, and assigned to an axis through the PLC or softkey table. This reference walks through the hardware, machine data (MD), PLC interface, and commissioning steps for retrofitting a +5 V TTL pulse handwheel on a lathe fitted with the 810T GA1 package.

The handwheel channel on the 810T GA1 accepts up to three handwheels simultaneously. Each handwheel is wired to its own pair of differential inputs (Track A and Track B, 90° quadrature, +5 V) on the handwheel interface card, and the control resolves the pulses to increment/decrement counts for the assigned axis. A four-position (or N-position) rotary selector switch on the operator panel — wired to the PLC — selects which axis the active handwheel drives at any moment. Alternatively, the operator can choose the assignment from a softkey on the 810T display.

Prerequisites

• Sinumerik 810T GA1 control, software version GA1 (Function blocks and machine data are GA1 specific; later SW packages use a different MD layout).
• Spare slot on the I/O submodule rack for the handwheel interface card (6FX1 121-x series or equivalent) — the handwheel module typically piggybacks onto the existing I/O block using the front-panel connector.
• Handheld or panel-mounted +5 V TTL pulse generator: 100 pulses/rev or 1024 pulses/rev types are both supported; 100 ppr is the factory default and provides smoother low-speed jogging on the 810T.
• Axis selector switch (rotary, 3-position minimum for X / Z / no-select; 4-position if a third axis or "rapid" detent is desired).
• Reference materials: Sinumerik 810T GA1 Installation Instructions (Installation List / Aufstellungsliste) and the PLC Programming and Interface Description for the 810T. Both are available from the Siemens Industry Online Support portal under product "SINUMERIK 810T" with the GA1 software filter.

Handwheel Interface Hardware

The handwheel interface is physically implemented on a sub-module that mounts on the front connector of the central I/O block (the "interface module" referenced in field-service documentation). Three differential input pairs are available, one per handwheel. The pin assignment on the 6FX1 handwheel connector is shown below.

Pulse Generator Signal Requirements

Machine Data Configuration: MD 5004

MD 5004 is the master "handwheel configuration" word on the 810T GA1. Bits 0, 1, and 2 each enable one handwheel; further bits select the operating mode and the weighting of the pulse generator.

The MD is entered on the commissioning screen as a decimal integer, but the individual bits are what determine behavior. Examples:

• One handwheel, softkey enable, ×1 weighting (100 ppr): MD 5004 = 0001 1001 binary = 25 decimal.
• Two handwheels, softkey enable, ×10 attenuation (1024 ppr): MD 5004 = 0001 0011 binary = 19 decimal.
• Three handwheels, no softkey (PLC switch only), ×1: MD 5004 = 0000 0111 binary = 7 decimal.

PLC Interface and Axis Selector Wiring

The handwheel-to-axis assignment is performed by the PLC, which writes three control bits per handwheel into the I/O image. The 810T GA1 reserves three groups of three consecutive outputs on the PLC for this purpose:

Exactly one bit of each group must be HIGH at any time. On a two-axis lathe (X, Z) only Q17.0 (HW1 → X) and Q17.1 (HW1 → Z) are typically used; Q17.2 must never be energized unless a third axis is configured in MD 5003.

PLC Logic Outline (Structured Text / AW excerpt)

The user-programmed FB must debounce the switch inputs, enforce single-bit selection (priority encoder: position 0 → X, position 1 → Z, position 2 → none), and copy the result to Q17. Skeleton in AW (Anweisungsliste) form:

NETWORK 1   ; debounce switch inputs
  U   E0.0       ; switch position 0 (X)
  UN  E0.1
  =   M10.0      ; X-selected
  U   E0.1       ; switch position 1 (Z)
  UN  E0.0
  =   M10.1      ; Z-selected

NETWORK 2   ; drive Q17 outputs
  U   M10.0
  =   A17.0      ; HW1 → X
  UN  M10.0
  U   M10.1
  =   A17.1      ; HW1 → Z
  UN  M10.0
  UN  M10.1
  =   A17.2      ; HW1 → none (spare)

Softkey Assignment (Alternative to Hardware Switch)

If MD 5004 bit 4 is set, the operator can select the handwheel-to-axis binding from a softkey on the 810T display. The softkey page writes the same bits as the PLC program, and the PLC program can read back the active state from NCK interface words (DB38 / DB39 on the 810T GA1). With this mode active, the hardware selector switch is optional — but most lathe retrofits keep both for redundancy: the switch provides tactile selection for the operator while the softkey page is used during setup.

Step-by-Step Installation Procedure

1. Power down and lock out the machine and the 810T control cabinet. The handwheel interface is not hot-pluggable.
2. Mount the handwheel interface card on the front connector of the central I/O block (slot per the GA1 Aufstellungsliste). Verify the ribbon connector seats fully.
3. Route the handwheel cable through the cable duct to the operator panel. Use shielded twisted pair (Belden 9501 or equivalent) for the A+/A- and B+/B- pairs; ground the shield at the cabinet end only.
4. Wire the pulse generator to the matching connector pins (1, 3, 4, 5, 6 for HW1). Confirm +5 V at pin 1 with a meter before plugging the handwheel in.
5. Mount the selector switch on the operator panel. Wire the common to a 24 V DC source through the panel I/O terminal block; wire the three positions to free inputs I0.0, I0.1, I0.2 (or any unused inputs on the 810T I/O).
6. Modify the PLC user program (STEP 5 on S5-130W, or the equivalent COM 810T tool) to add the debounce + priority-encoder network shown above. Compile and download to the 810T.
7. Edit MD 5004 from the commissioning screen. Enter the decimal equivalent of the desired bit pattern (e.g., 25 for one handwheel + softkey + ×1).
8. Save the new MD and PLC to a memory submodule before powering off.
9. Power up the control and verify no alarms on power-up. The "Handwheel" softkey should appear on the operator page if bit 4 of MD 5004 is set.

Verification and Testing

1. With the control in JOG mode and the axis enable (Feed/rapid override ≥ 0%) engaged, set the selector switch to position 0 (X). Turn the handwheel one click clockwise — the X axis actual value should increment by 0.001 mm (×1 weighting) or 0.010 mm (×10 weighting).
2. Set the switch to position 1 (Z). Turning the handwheel should move the Z axis; X must stay still.
3. Set the switch to the centre (no-select) position. Turning the handwheel must NOT move any axis. If motion occurs, the priority encoder is wrong (two Q17 bits HIGH simultaneously → alarm 2130).
4. Reverse the handwheel direction by swapping A+ with A- on the connector. Verify with a single click in the opposite direction. Direction sense must match the on-screen arrow.
5. From the softkey page, force the assignment to Z and verify that the selector switch can override it on the next scan (or vice versa, depending on the PLC logic).
6. Check that the feed-override potentiometer still affects the handwheel-driven axis (810T GA1 scales handwheel pulses by the active feed-override).

Troubleshooting Matrix

PLC Program Tips

• Keep the handwheel-selection logic in its own FB so it can be re-loaded without recompiling the whole S5 program.
• If you later add a third handwheel (for a sub-spindle or tailstock), enable bit 2 of MD 5004 and re-route the corresponding PLC outputs to Q21.0–Q21.2. The wiring pattern is identical.
• If the 810T is replaced by an 810T GA3 / GA4 in future, MD 5004 layout changes — bit meanings shift right and additional bits 8–11 control handwheel simulation from the HMI. Re-validate the parameter map after any SW upgrade.

Safety and Best Practices

• Always wire the handwheel enable signal through the existing axis-drive-enable chain; the handwheel must not be able to drive an axis when the drive is disabled (E-STOP open, guard open, etc.).
• Use the smallest practical pulse weighting for the application. ×1 weighting at 100 ppr gives 0.001 mm per click at the default internal scale, which is the safest resolution for manual jog on a lathe.
• Document the final MD 5004 value, the PLC FB version, and the wiring diagram in the machine's electrical dossier. Future service engineers will look there first.
• Replace any handwheel with an EMG-STOP button integrated in the housing. The 810T supports a hardware handwheel-enable input (I0.7 by convention on the GA1) that must be HIGH for handwheel pulses to reach the NCK.

Field Commissioning Checklist

• [ ] MD 5004 set, value documented in machine file
• [ ] PLC FB compiled, downloaded, backed up to EPROM / memory card
• [ ] Selector switch wired and labelled (X / Z / —)
• [ ] Handwheel enable input wired through EMG-STOP chain
• [ ] Direction sense verified in JOG with override at 10%
• [ ] Softkey page functional (if enabled)
• [ ] 100-pulse counting test passed at both weightings
• [ ] No alarm 2130 on power-up or switch transition
• [ ] Shield grounded at cabinet end only
• [ ] Cable routed away from spindle VFD output (≥ 200 mm)