TCsi - Absolute Encoder Adjustment (Machine Zero Reset)

This procedure overwrites machine zero on X and Z1. The archive is the only way back to the machine's current state.

Create a complete machine archive before touching anything.

Archive Current System

Press [JOG] and [REF POINT] on the MCP.

On the [Machine] screen, look for the reference icon beside each axis name: MQ1, MX1 and MZ1.

The black and white circle means the axis has a reference. No icon means it does not.

All servo axes must show the icon before the machine is operational.

The chuck (MC1) does not display a reference icon because it is not a servo axis and does not require referencing.

The icon means only that MD34210 = 2, that the control has marked the reference valid. It does not prove the reference is correct.

MD34090 $MA_REFP_MOVE_DIST_CORR. The calibration itself, the offset between machine zero and the encoder zero. The control writes it, not you.

MD34100 $MA_REFP_SET_POS. The coordinate you tell the control the axis is standing at. This is your input.

MD34210 $MA_ENC_REFP_STATE. Records whether this axis is referenced. Siemens calls it the adjustment status of the absolute encoder. It holds one of these values:

0. Not calibrated. The encoder has no reference to the physical position.

1. Calibration enabled. The control will accept MD34100. This is the state you set.

2. Calibrated. Written by the control, not by you.

With MD34210 = 1, the control transfers MD34100 as the absolute value and computes MD34090 from it. That is the whole mechanism this guide runs on.

Set Manufacture Password.

Go to [Setup] → [Mach. Data] → [Axis MD] → [Select Axis] → [MQ1/SERVO] → [OK].

Confirm the top right banner reads MQ1 before entering anything.

Press [Search], enter 34210, press [OK].

Set MD34210[0] = 1.

This determines which DB address to use in Step 6.

All LTY machines are on New-PLC

On the control, go to [Diagnostics] → [Version].

Locate the PLC User Program version.

If version starts with 05.XX.XX, it is New-PLC.

If version starts with 01.XX.XX, it is Old-PLC.

Go to [Diagnostic] → [NC/PLC Variable]

In an empty row under Variable, enter the proper bit:

Old-PLC → DB34.DBX4.7

New-PLC → DB37.DBX4.7

Set the Format to [B].

On the MCP, press both [JOG] and [REF POINT].

Press [Change], enter 1, press [Input] → [OK]. The bit returns to 0 on its own.

Confirm the Q axis now shows the reference icon.

Mount a turret toolholder with a square, machined face in Position 1.

For TC820si: Use a boring bar block or standard OD (Outside Diameter) turning tool holder with a flat machined face (e.g., facing or roughing tool block).

For TC820LTY: Use a radial live tool holder (facing the spindle) with a square machined face.

Insert a centering indicator into the spindle

Jog X and Z to bring the indicator into contact with the toolholder face.

Go to [Machine], press [Act. values MCS] to display Machine Coordinates.

Sweep the X-axis back and forth; adjust Z until runout is < 0.001" across +X and −X.

This Z-axis position defines the turret’s X0 mechanical centerline.

Go to [Setup] → [Mach. Data] → [Axis MD] → [Select Axis] → [MX1/SERVO] → [OK].

Press the [Search] button and enter 34210, then press [OK].

On the MCP, turn on [JOG] and [REF. POINT].

Set MD34210[0] = 1

For TC820 & TC820LTY: Press [+X].

Confirm the X-axis shows the reference icon.

Z0 is established by bringing the turret face into contact with a known-height reference object placed against a defined machine surface.

The Z-axis reference value is calculated by subtracting the reference object’s height from the machine position at the moment of contact.

The correct surface to place the reference object depends on the machine model and serial number.

TC820si: Serial STA60001–STA60043: Reference from the chuck face.

Serial STA60044 and later: Reference from the spindle face.

TC820LTYsi Serial STP60001–STP60013: Reference from the chuck face.

Serial STP60014 and later: Reference from the spindle face.

TC820LTY-Ssi All models reference from the spindle face.

MD34100 tells the control what machine coordinate to assign to the axis during encoder referencing.

This value must reflect the height or distance of the physical reference used — such as a 1-2-3 block, 6.000" gauge block, or spindle-to-spindle spacer.

Set per axis, MD34100 (Step 11) must be entered before referencing using MD34210 (Step 15) to ensure the encoder aligns with the actual position.

Set MD34100 to match the exact height of the measuring tool or reference stack used when physically referencing the Z1 axis.

This value will be assigned as the machine coordinate for Z1 during encoder calibration.

TC820 / TC820LTY: Use the block height touched off in Step 12.

TC820LTY-S: Use the calculated value from Step 13 & 14: Z1 Reference Value = [Block Height] + A + B

Once you have the correct value:

Go to [Setup] → [Mach. Data] → [Axis MD] → [Select Axis] → [MZ1/SERVO].

[Search] and enter the value in MD34100.

This must be set before referencing the encoder in Step 15.

Remove any tool holder from the turret and clear the spindle face (remove any part or chuck jaws).

Place a known-height precision block on the correct surface (see Step 9 for which face to use).

Slowly jog the Z-axis until the turret face makes light contact with the block.

Ensure there is no visible gap, but do not compress or deflect the block.

This contact point is +X.XXX" from actual Z0, where X.XXX = height of your reference block.

Go to [Machine], press [Act. values MCS] to switch to machine coordinates.

Note the MZ1 machine position while the turret face is in contact with the block — this value will be used to set MD34100 in Step 11.

Place a precision gauge block (6.000" or longer) firmly against the main spindle face.

Jog the turret forward until the tool face makes light contact — do not compress the block.

Confirm the previously recorded block height, A, and B values from Step 13.

Calculate the total: Z1 Reference Value = [Block Height] + A + B.

Go to [Machine] → [Actual Values MCS] to display machine coordinates.

Record the MZ1 machine coordinate at the moment of contact.

This value will be used to set MD34100 in Step 11.

Before continuing, make sure MD34100 has been set correctly in Step 11. This value defines the Z1 position the control will assign during encoder referencing.

Go to [Setup] → [Mach. Data] → [Axis MD] → [Select Axis] → [MZ1/SERVO] → [OK].

Press the [Search] button and enter 34210, then press [OK].

On the MCP, turn on [JOG] and [REF. POINT].

Set MD34210[0] = 1

For TC820 and TC820LTY: Press [+Z].

Confirm the Z-axis shows the reference icon.

Confirm all required axes display the black/white reference icon: Q, X, Z1, and Z2 (for TC820LTY-S).

Archive machine state to preserve encoder references.

Archive Current System Dozuki

Send new archive to TRAK Tech Support or upload to Config Folder

TC820si Config Folder

TC820LTYsi Config Folder