An older SL-5 equipped with a Fanuc 6T control—not a 6TB—may have X-axis signs opposite the desired convention: -X moves toward a larger diameter and +X toward a smaller diameter. The documented reversal method requires coordinated changes to overtravel wiring, jog inputs, motor armature polarity, encoder feedback, and control parameters. Changing only one subsystem can create a mismatch between commanded motion, feedback, and travel protection.
Identify the Required Direction Changes
The reversal affects multiple functions, so treat the wiring and parameter edits as one coordinated modification. Before disconnecting conductors, isolate electrical power according to the machine's established electrical-safety procedure and record every original wire position and parameter value.
| Subsystem | Required change |
|---|---|
| Soft overtravel | Swap L1 and L2 at the magnetics-cabinet terminal block. |
| X-axis jog selector | Exchange the two-wire X+ pair with the two-wire X- pair. |
| Motor armature | Reverse armature connections using one of the documented connection-point options. |
| Encoder | Reverse encoder connections using one of the documented connection-point options. |
| Fanuc 6T parameters | Edit 12.0, 143, 147, and 82. |
Reverse the X-Axis Wiring
- Swap soft-overtravel wires
L1andL2on the terminal block in the magnetics cabinet. - At the operator-panel jog lever, swap the two wires assigned to
X+with the two wires assigned toX-. - Reverse the motor armature at only one end of the cable. At the motor, exchange the conductors on pins
CandDwith those on pinsFandG, respectively. Alternatively, at the other cable end, exchangeA5XwithA7XandA6XwithA8X. - Reverse the encoder wiring at only one connection point. At the motor, exchange
AwithBandDwithE. Alternatively, on NC connectorCN105, exchange pin16with18and pin17with19.
The armature and encoder alternatives describe opposite ends of their respective cables; do not perform both alternatives for the same circuit.
Apply the Fanuc 6T Parameter Changes
| Parameter | Change |
|---|---|
12.0 |
Change from 1 to 0. |
143 and 147
|
Exchange their data while keeping 143 negative and 147 positive. |
82 |
Change only its sign. |
The instruction for parameters 143 and 147 is sign-sensitive. It does not support blindly interchanging the complete signed entries: the resulting value in 143 must remain negative, and the resulting value in 147 must remain positive. Record the original entries and stop for control-specific documentation or qualified service support if the intended magnitude exchange is unclear.
Verify Motion and Overtravel Protection
After completing all wiring and parameter changes, verify X-axis direction independently in jog, handle, G01 feed, and zero-return functions. Begin at minimum rapid or jog speed and confirm that displayed position, commanded direction, and physical tool motion agree.
At minimum rapid or jog, intentionally approach each hard overtravel switch and confirm that both switches stop travel in the correct direction. Do not return the machine to production until jog, handle, G01, zero return, and both hard-overtravel directions operate correctly.
FAQ
Can Fanuc 6T parameter 12.0 alone reverse the SL-5 X axis?
No. The documented method combines the 12.0 change with soft-overtravel, jog-selector, armature, encoder, and parameters 143, 147, and 82.
Which Fanuc 6T parameters change when reversing X direction?
Change 12.0 from 1 to 0, exchange the data of 143 and 147 while retaining their negative and positive signs respectively, and reverse only the sign of 82.
How do I test the SL-5 after reversing the X axis?
Check jog, handle, G01, and zero return, then use minimum rapid or jog to approach both hard-overtravel switches and verify that each stops motion in the correct direction.