Manual – IPOSplus®
139
12
P95x absolute encoder (SSI)
P9xx IPOS Parameters
12.6.3 P952 Cycle frequency
Setting range: 1 – 200%
Defines the cycle frequency at which absolute encoder information is transmitted from
the encoder to the inverter. A cycle frequency of 100% corresponds to the nominal fre-
quency of the encoder in relation to a 100 m cable length.
12.6.4 P953 Position offset
Setting range: –(2
31
–1) – 0 – 2
31
–1
The position offset P953 only needs to be set on incremental encoders; it should be set
to 0 for other encoders.
Note: The position value will be recalculated and overwritten automatically after suc-
cessful completion of the reference travel.
12.6.5 P954 Zero offset
Setting range: –(2
31
–1) – 0 – 2
31
–1
Zero offset is used for assigning the value you want to a specific position. The range of
values can adopt positive or negative position values. The maximum valid parameter
must not be exceeded. The limit is determined by the range of values of the numerator
(2
31
) and the range of values of the absolute encoder. Move the drive to a known posi-
tion. Read off the value of variable H509 ACT.POS.ABS and enter the following value
in parameter P954 Zero offset: P954 = Variable H509 – required value.
The required value is the display value you wish to have for the current position.
12.6.6 P955 Encoder scaling
Setting range: x1 / x2 / x4 / x8 / x16 / x32 / x64
Before
setting P955, make sure that P942 and P943 are set to "1".
The significance of the travel resolution of the motor encoder and absolute encoder is
adapted. The parameter is set so the travel information ratio between the motor encoder
and the absolute encoder is as close to "1" as possible. First set the parameter to "x1".
To do this, note the values in variables H509 and H511.
• Move the drive by about 1000 increments (H511).
• Calculate the difference between the values you wrote down and the current values:
– H509 new – H509 old = H509 difference
– H511 new – H511 old = H511 difference
• Calculate the quotient from H511 difference divided by H509 difference. Set
parameter P955 Encoder scaling to the value that is closest to the calculated
quotient.
Important
: Encoder scaling directly affects parameters P900 Reference offset
(page 123), P942 Encoder factor numerator (page 134), P943 Encoder factor denomi-
nator (page 134), P954 Zero offset (page 139) as well as the parameter group P92x
IPOS monitoring (page 131). All positions of the IPOS
plus®
program have to be adjusted
when using the external encoder. The setting of all listed parameters has to be adjusted
every time the encoder scaling is changed.
12.6.7 P956 CAN encoder baud rate
Setting range: 125 kbaud / 250 kbaud / 500 kbaud / 1 Mbaud
P
i
f
kVA
Hz
n