HEIDENHAIN ERN 1387.020-2048 Rotary Encoder: Complete Technical Guide for Industrial Automation

13 Ιανουάριος 2026

Historical parts record: Photos and notes below belong to this record. Confirm the offered unit’s full model, condition and available test evidence before ordering.

What is the HEIDENHAIN ERN 1387.020-2048?

The ERN 1387 is HEIDENHAIN's incremental rotary encoder for drive feedback — the shaft-mounted pulse source a closed-loop drive counts to know its speed and position. This unit's end-cover engraving gives the full identity: ERN 1387.020-2048, K9, 5 V ±5%, ID 385487-03, SN 27 198 321C, with the heidenhain.de marking and a barcode. It is a tested pull, not new stock — a second-hand removal with a 3-month warranty as recorded at intake on 23 October 2025 — and the housing wear in the photos shows the service history honestly. One unit; all five photos and the inspection video show this exact encoder.

2 min readContent reviewed 8 October 2026

Part details

ERN 1387.020-2048, as engraved on the end cover
Field	Value
Brand	HEIDENHAIN (www.heidenhain.de on the cover)
Model	ERN 1387.020-2048 incremental rotary encoder — 2048 line count per the model code
Variant	K9 (connection code on the engraving)
Supply	5 V ±5% (engraved)
ID / Serial	ID 385487-03, SN 27 198 321C, with barcode
Shaft	Solid plain shaft, sealed double bearing seat
Mounting	Stainless three-arm stator bracket with slotted ears on a clamp band
Condition	Second-hand removal (tested pull), housing wear visible; 3-month warranty as recorded at intake, 23 October 2025

Scroll sideways to see the full table.

Values are read from the end-cover engraving and the photographed construction in the photo set.

Where an ERN 1387 earns its keep

An incremental encoder does the simpler half of position feedback: it emits a pulse train whose frequency is the speed and whose count is the distance — no absolute memory, but exactly what a servo drive's commutation and velocity loop need. The ERN 1387 family is HEIDENHAIN's workhorse for that job on machine-tool spindle and feed drives, and the 2048 in this unit's model code is the line count the scan unit produces per revolution — dense enough that the drive's interpolation electronics derive a very fine effective resolution from the sinusoidal signals. The K9 variant marking on the cover is HEIDENHAIN's connection-code field; the engraved 5 V ±5% is the supply window the scanning electronics expect.

As a pull, this unit has the honest marks of service: the housing shows scuffing and the finish is worn where a coupling or bracket rubbed, the stainless three-arm stator bracket is present and straight, and the shaft rides true in its sealed bearing seat with the plain cylindrical end a standard coupling clamps onto. The end cover carries the full laser engraving — model, variant, supply, ID 385487-03 and serial 27 198 321C with its barcode — so the unit can be matched to HEIDENHAIN's records before it goes back onto a drive. For a machine whose encoder failed, a tested original at a fraction of new-unit cost is the practical repair, and the three-month intake warranty covers the window a bench test needs.

Photos

All images below are original KOEED warehouse photos. Click any photo to view it full size.

Side with shaft and cable — Side view: the two-part aluminium housing, the clamp band with its screws, the solid shaft and the cable exit with the workshop sticker — the wear of a working unit, shown as found.

Other side — The other side: the stainless three-arm bracket, the shaft end and the cable tail with its sealed tip.

Shaft end angled — The shaft end angled: plain cylindrical shaft in its sealed bearing seat, the coupling side a standard clamp grips.

Engraved end cover — The engraved end cover: ERN 1387.020-2048, K9, 5V ±5%, ID 385487-03, SN 27 198 321C with barcode and the heidenhain.de mark.

Engraving second angle — The engraving from the second angle — every identity field legible for matching against HEIDENHAIN's records.

Inspection video, recorded at the Koeed warehouse before dispatch.

For the absolute-position sibling from the same brand, see the HEIDENHAIN EQN 1325 absolute encoder — EnDat position readout without homing, documented from the same warehouse.