64
SM-Universal Encoder Plus User Guide
www.controltechniques.com
Issue Number: 6
Words 5 to 8 are the position with the least significant bit in word 5. Below are the
numbers laid out in the correct order:
Shifted to turns and position (which is 12 bits then 13 bits):
So the absolute position is 1860/7486 which should be compared to the displayed
interpolated position of 1860/7485.
8.1.2
SSI and EndAt
Encoder Comms Resolution
Where encoder comms alone is used the encoder single turn comms resolution Pr
x.11
and the encoder turns bits Pr
x.09
must be set correctly. Although Pr
x.11
can be set to
any value from 0 to 32, if the value is less than 1, the resolution is 1 bit.
Some SSI encoders include a power supply monitor alarm using the least significant bit
of the position. It is possible for the drive to monitor this bit and produce an EnC6 trip if
the power supply is too low see Pr
x.17
. If the encoder gives this information the comms
resolution should be set up to include this bit whether or not it is being monitored by the
drive.
It is possible for the drive to set up this parameter automatically from information
obtained from the encoder via the EndAt interface see Pr
x.18
.
Encoder Turns
When an encoder with comms is used, Pr
x.09
must contain the number of bits in the
comms message used to give the multi-turn information. For a single turn comms
encoder Pr
x.09
must be set to zero. It is possible for the drive to set up this parameter
automatically from information obtained from the encoder via Hiperface or EndAt
interfaces during auto configuration.
Encoder Comms Baud Rate
Pr
x.14
defines the baud rate for the encoder comms when using SSI or EndAt
encoders.
When encoder comms is used alone the time taken to obtain the comms position must
be 200
µ
s or less.
There is a delay associated with obtaining the position from an encoder using comms
alone to transmit the position. The length of this delay affects the sample rate and timing
Word 8
Word 7
Word 6
Word 5
116
78
159
00
0111 0100
0100 1110
1001 1111
0000 0000
0111 0100 0100
(end of turns and start of the position)
1 1101 0011 1110
1860
7486
Pr value
Parameter string
Baud rate
0
100
100k
1
200
200k
2
300
300k
3
400
400k
4
500
500k
5
1000
1M
6
1500
1.5M
7
2000
2M
Содержание SM-Universal Encoder Plus
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