ERMA SSI 9005, Instruction Manual, Page: 34 / 40

Ex am ple 2:
Pro ces sing the data sent from an en co der the SSI 9005 nor mal ly ex pects that the first
bit which is sent is the MSB of the po si ti on data. Now some ty pes of en co ders are
sen ding ot her in for ma tions (e.g.: a pre sent bit) or ze ros be fo re the MSB of the po si ti -
on data is sent.
E.g.: it is pos si ble that you have an en co der which is said to be an14 bit en co der but
the re so lu ti on is only 12 bit and the first two MSBs are ze ros; that would lead to an in -
cor rect mea ru red va lue. The pa ra me ter P0-16 can be used if lea ding ze ros in the en -
co der data should not be ta ken into con si der ati on. If you have an en co der which is
sen ding ze ros be fo re the po si ti on data you have to do the pro gram ming as fol lows:
-set the pa ra me ter in P0-00 to the com ple te num ber of bit (ze ros in clu ded)
-set the pa ra me ter in P0-16 to the num ber of ze ros which are used as lea ding bits be -
fo re the ac tu al po si ti on va lue starts.
Ex am ple 3:
You' ve got an en co der which is sen ding sta tus bits be fo re the po si ti on data as well as
af ter the po si ti on data. The po si ti on data have a width of 24 bits and be fo re the MSB 2
sta tus bits are sent and af ter the LSB two more sta tus bits are sent. The SSI 9005
shall work in the sla ve mode. The data from the en co der shall also be sent to a com -
pu ter which pro ces ses both the sta tus bits as well as the po si ti on data. The SSI 9005
shall only pro cess the po si ti on data. The re fo re the fol lo wing set tings have to be
made:
• Pa ra me ter 0-00 has to be set to 28 which is the sum of the 24 bits of the po si ti on
data and the 2 x 2 sta tus bits.
• Pa ra me ter 0-16 has to be set to 2 to re mo ve the 2 sta tus bits be fo re the MSB of the
po si ti on data.
• Pa ra me ter 0-17 has als to be set to 2 to re mo ve the 2 sta tus bits af ter the LSB of the
po si ti on data.
With the se set tings the dis play will show the cor rect po si ti on data of the en co der
even when sta tus bits are tran fe red to get her with the po si ti on data. (Plea se see 9.1
for sla ve pro gram ming)
34 ERMA-Electronic GmbH
9. Software functions
SB SB MSB SB SB LSB
Position data
State bits;
will be removed State bits;
will be removed
Total data width: 28 bit