HeidenhainROD 450 Incremental Rotary Encoder, 2540 Lines, 10 mm Solid Shaft, Integral Bearing

Product Description

What this part is

A Heidenhain ROD 450 incremental rotary encoder, 2540 lines per revolution, Heidenhain ID 251 568. It is a shaft-driven feedback device with an integral bearing: the shaft turns and the encoder delivers quadrature incremental signals plus a reference mark, which the counter, drive or CNC resolves into position, direction and speed.

Decoding the designation

ROD: rotary encoder, incremental, integral bearing, solid shaft for use with a separate shaft coupling. 450: the model within the ROD 400 range. 2540: line count, that is, 2540 signal periods per revolution. 251 568: Heidenhain ID number. The trailing -1N is the variant marking on this unit.

Why 2540 lines

There are exactly 2540 hundredths of a millimetre in an inch, and 2540 divides cleanly by 10, 20 and 127, the numbers that arise when an imperial-leadscrew machine displays and positions in inches without a scaling factor. Counts of this kind belong to imperial machine tools, imperial-pitch ballscrews and inch-based retrofits. A 2500-line unit in place of a 2540-line unit produces a 1.6% position error.

Published specifications

Type: incremental rotary encoder with integral bearing, Heidenhain ROD 400 range. Model: ROD 450. Base number: ROD 450. Series: ROD 400. Line count: 2540 per revolution. Measuring steps after 4-fold evaluation: 10 160 per revolution. Shaft: 10 mm solid shaft, for a separate shaft coupling. Mounting: synchro flange, coupled to the drive or spindle via a separate rotor coupling. Reference mark: one. Heidenhain ID: 251 568. Variant marking on unit: -1N. Quantity: one encoder. Country of manufacture: Germany.

Mounting data

Mounting: synchro flange. Shaft: 10 mm solid. Coupling: separate flexible or stator coupling, which absorbs the misalignment and axial float that would otherwise pass into the encoder’s own bearing.

Interchange references

Line count: 2540. Output interface: the Heidenhain ROD ranges were supplied with TTL square-wave, HTL and analogue outputs depending on the model, and the interface has to match what the control expects even where the flange and shaft bolt up identically. ID number 251 568 pins the exact build. Other ROD 400 models, among them the ROD 426, ROD 436, ROD 466 and ROD 486, share the family and the mounting concept and differ in shaft diameter, interface and available line counts. Also written ROD450, ROD-450-2540, ROD 450.2540, ID 251568, 251-568-1N and 251 568-1N.