JVL MIS17 Series User Manual page 120

5.7 SSI encoder/sensor interface
5.7.3 Setup and operation of the SSI function when NOT using MacTalk.
Following lines describe how to access relevant registers when having a SSI device con-
nected.
When reading the data from the SSI device the data will be places as a signed 32 bit inte-
ger in register 47 shortly after the read command have been executed.
The time before data is present can be calculated after following formula:
Total time from the read command 321 is executed until valid data is present is equal:
Time = Prepare time (timer) + (1/ Clock frequency * (Number of Data bits+1))
Example:
Encoder used have following setup:
Prepare time = 100uS (0.0001 sec.)
Clock frequency = 10kHz (10000Hz)
Number of data bits = 25
0.0001+ (1/10000 * (25 + 1) = 0.0027 sec. = 2.7ms
Note:
If noise have affected the signal the time before valid data is presented will be longer.
Depending on the specific setting for the data validation function.
The position data from the encoder is presented in register 47 as shown below.
Register 47 - «EXTENCODER» (External encoder data) - Signed 32 bit integer.
31 30 29 28 27 26 25 24 23 22
Register 107 - «SSI_SETUP1» - Unsigned 32 bit integer.
31 30
«Read
retries»
(2^n)
Register 111 - «SSI_SETUP2» - Unsigned 32 bit integer.
31 30
120 JVL Industri Elektronik A/S - User Manual - Integrated Stepper Motors MIS17x, 23x, 34x, 43x
21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Position data available as a signed 32 Bit integer
29 28 27 26 25 24 23 22 21
«Max. sample deviation»
(1-8191)
29 28 27 26 25 24 23 22 21
Not used / reserved
20 19 18 17 16 15 14 13 12
«Clock frequency»
(x 10kHz)
20 19 18 17 16 15 14 13 12
11 10 9 8 7 6 5 4
«Number
of
samples»
11 10 9 8 7 6 5 4
«Prepare time»
(1µS * n)
«Gray to
Bin converter»
Activator
(Set to 1" for Gray to bin "
Set to "0" for no conversion)
TT2482-01GB
3 2 1 0
«Number of
databits»
3 2 1 0
TT2483-01GB