what does that mean when talking about "additional clock switch" in 84E's manual

[lnn365]

Dear Sir,

I do not know what does that mean when talking about "additional clock

switch" in page 21 of ACC-84E's manual.

I have already read Endat's specification, and it says without delay compensation, the maximum transmission rate is 2M, and from 84E's manual we get to know 84E does not have this circuit builtin, so the maximum transmission rate should be 2M? so why does the manual list settings for transmission rate above 2M?

 

Another question, from Endat's specification, we know that Endat is similar to SSI, all using external clock signal to drive the bit transition, so, shouldn't the clock setting for Endat be similar to that of SSI's(Serial clock frequency = bit transmission frequency)? why does 84E's manual says "The serial

clock frequency is set 25 times higher than the external clock frequency, which is the bit transmission frequency fbit (MHz)"?

 

yours sincerely,

Ning Liu

[Jay Lee]

Hi,

 

In Acc84E manual, there are 2 types of clock setting regarding EnDat.

one is without additional clock switch, and the other one is with additional clock switch.

the additional clock switch is referring to HEIDENHAIN EnDat EIB series.

EIB serial switch usually has up to 16MKhz clock frequency, and that is why we have 2 tables of common serial clock frequency settings.

The table without switch box is in the range from 250 Khz to 2 Mhz.

The table with switch box is in the range from 4.16 Mhz to 12.5 Mhz.

[lnn365]

Dear Jay,

Thank you very much for your reply, but it seemed you have forgotten the second question :)

And I am still a little puzzled about the first question, if we want to get higher transmission rate (higher than 2M), we can choose the encoder with the "additional clock switch" directly ? is it enough? without considering whether does PMAC have the delay compensation circuit buitin?

For the encoder we are currently using, RCN8510, its datasheet says its clock frequency can up to 16M, but 84E does not have delay compensation function, so can we set its clock frequency higher than 2M?

(I know you may wondering "you already have the encoder with you, why not test it". the fact is we have some problem when testing the motor, its speed is too low, so we guess the problem maybe lies in the configuration with 84E, and we also want to know how to choose the right encoder next time. )