Comparing Heidenhain's ND 287, ND 280, and ND 281B
Heidenhain's ND 280 is the second-most versatile of their small DRO's, after their flagship ND 287 model. The ND 280 will accept inputs from either linear or rotary incremental or absolute encoders, from three of the four generations of the company's types: the early 11uA current units, the later 1Vp-p models, and the current EnDat devices. The latest SSI units are not supported by the ND 280, but are compatible with the ND 287.
The 280 has a large, bright monochrome LCD display, with context-sensitive help, softkeys, and many programmable features. These include multiple languages, both USB and RS-232 serial ports for computer and/or printer interface, linear or non-linear compensation for encoder axis errors, graphical diagnosis of encoder performance, and a wide selection of interpolations. Its firmware can be upgraded via the USB port. It's versatile enough to satisfy the needs of most single-axis users.
The ND 287, with its color LCD, adds the provision for an optional second-axis input, and even supports arithmetic, algebraic, and trigonometric operations between the two. For example, you could display an angle by measuring the horizontal travel on one axis, the vertical travel on the second, and have the unit calculate and display TANGENT RISE (divided by) RUN. It will also enable simple addition and subtraction. For example, many milling machines have both a quill and a knee. With a linear encoder on BOTH axes, the ND 287 will display the TOTAL travel of both axes, so you'll always know your Z depth.
The ND 287 even has a third option, an analog input card, primarily intended for a temperature sensor. The 287 has a maximum interpolation factor of 4096, and at such high magnification, even very small temperature changes can affect readings. The temperature sensor can help compensate for these changes automatically, and help improve results.
We have both the ND 280 and ND 287 in our lab, and use both frequently. If they're out of your price range, even on eBay, you might consider the ND 281B. It's not quite as versatile or user-friendly, but is still compatible with both the 11uA and 1Vp-p linear or rotary, incremental or absolute encoders. It has dual M23 input connectors, the older round type, but only one can be active at a time. Still, if you work with older Heidenhain encoders, you'll save time and money on the adapter cables you'd otherwise need with the newer DRO's. We have two ND 281B's, both in use with MT-type probes.
After a lot of research, we consider Heidenhain among the best scale and DRO manufacturers. If you need high precision measurement, you can only do better with a MUCH more expensive laser system.
Verified purchase: YesCondition: Pre-owned