Heidenhain EnDat Serial Encoders: Incremental Line Counts

Question:

We have a question about Heidenhain ECN 1313 Series encoders. What does line count mean in Heidenhain encoders? We have two ECN 1313 encoders. One of them ECN 1313 512 62S12-78 and the other one is ECN 1313 2048 62S12-78 . Both of them have 8192 pulse per rev (in Mitchell System) and both of them have 8192 position per revolution in Heidenhain datasheets. However their difference is in Line Counts which one of them has 512 and the other one has 2048. 

And the last question can we replace these encoders with each other? (Because both of them the same ppr)

We read about this subject from 5000 EX manual, but we want to ask a professional (you) to be sure about it. Thanks for your help.

Answer:

Both encoders listed have the same serial absolute count (8192) but they have different number of incremental pulses. The Heidenhain EnDat Count Test is checking absolute position counts (serial data), not incremental counts. To test the incremental counts per revolution you need to look at the INCREMENTAL count field of Data Display. Perform one rotation on the encoder and the incremental count will be displayed. Remember that our system is always 4X the number of pulses from the encoder, so 512 pulses = 2048 counts and 2048 pulses = 8192 counts.

I would not recommend using the encoder as a replacement since the incremental counts don't match. Here is another way to see it:

ECN1313 512
Singleturn absolute count: 8192 (13 bits)
Multiturn absolute count: 0
Incremental pulses (count): 512 (2048)

ECN1313 2048
Singleturn absolute count: 8192 (13 bits)
Multiturn absolute count: 0
Incremental pulses (count): 2048 (8192)

EQN1325 2048
Singleturn absolute count: 8192 (13 bits)
Multiturn absolute count: 4096 (12 bits)
Incremental pulses (count): 2048 (8192)

Here is a memo on testing the incremental pulses, including the final page which describes a couple methods of incremental count test without an index pulse.
https://www.dropbox.com/s/0bnzwhyp5dnuh5y/MEMO_TI-5000JX_Testing_1Vpp_Sine_and_Inductive_Scanning_Gap.pdf?dl=0