80 JVL Industri Elektronik A/S - User Manual - Integrated Stepper Motors MIS23x, 34x, 43x
5.4 SSI encoder/sensor interface
5.4.4 Setup and operation of the SSI function when NOT using MacTalk.
(below descr. covers all MIS and SMC products)
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 formular:
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))
Exampel:
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: (only for MIS34x/MIS43x and SMC85)
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.
A few differences exist between the product families concerning following registers.
MIS23x / SMC75:
Register description.
TT2482-01GB
31 30 29 28 27 26 25 24 23 22
Position data available as a signed 32 Bit integer
Register 47 - «EXTENCODER» (External encoder data) - Signed 32 bit integer.
2120191817161514131211109876543210
«Clock frequency»
(x 10kHz)
«Number of
databits»
«Prepare time»
(1µS * n)
«Wait time»
(1µS * n)
TT2484-01GB
Reserved
Disable
interrupts
15
15
14
14
13
13
12
12
11
11
10
10
9
9
8
8
7
7
6
6
5
5
4
4
3
3
2
2
1
1
0
0
Register 107 - «
I_
ETUP1» - Unsigned 16 bit integer.
Register 111 - «SSI_SETUP2» - Unsigned 16 bit integer.
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