Rockwell Automation is offering the Allen-Bradley Bulletin 844D blind-shaft and through-shaft incremental encoders. These devices can be mounted directly to the monitored shaft via a split collar clamp on the encoder, eliminating the need for mounting plates and flexible couplings.

As a result of the direct mounting overall cost and size are reduced considerably. With this encoder, the length of the motor shaft becomes noncritical, as long as it meets the minimum length of 18 mm (blind shaft models support a maximum 50 mm shaft length). Through-shaft models are installed by inserting the monitored shaft completely through the encoder, while blind-shaft models only require insertion of the end of the shaft. Shaft position is converted to digital pulses in an 'A quad B' format.

An important feature of the 844D is its high frequency response: 300 kHz for line drivers up to 8192 PPR, and 600 kHz above 8192 PPR. This allows both high resolution (10 000 and 16 384 PPR) and high shaft speed (over 2000 RPM at 16 384 PPR).

Noteworthy features include:

* A zero index channel is included with all models.

* Blind-shaft and through-shaft front coupled models.

* Mounting plate and flexible coupling not required.

* 360 to 16 384 PPR (pulses per revolution)

* 89 mm (3,5") diameter housing.

* Supports 1/2 to 11/8" diameter shafts.

* Cable, connector or terminal block connection options.

* Superior shaft seals for high-speed operation.

* Rugged steel shaft and clamp.