6
4. Further applicable documents
All technical data is given in the corresponding
data sheets of the encoders. You will find there
the mechanical and electrical characteristics of
the SIL and ATEX-SIL encoders.
5. Data Transmission
5.1 Sine and Cosine Signals
A -
= Sin; B –
= Cos
The analogue signals must be measured differ-
entially, i.e. A minus
gives the sine, B minus
gives the cosine.
The signals A,
, B,
each have an ampli-
tude of 0.5Vss with an offset of +2.5V to 0V.
Measured differentially, the sine and cosine sig-
nals have an amplitude of 1Vss, with a phase-
shift of 90°.
The resolution of the incremental track is
2048 sine/cosine periods.
B
A
A
B
A
B
Offset:
2,5V +/- 50mV
Offset difference A-B max. 25mV
Amplitude: 1Vss +/-100mV
Amplitude difference A-B max.
40mV
Terminating resistor:
120 Ohm (A –
; B –
)
A
B
The validity of the safety function must be
checked with the function sin²(x) + cos²(x) = 1.
The recommended tolerance range for the
encoder lies between 0.5 and 1.5. However this
value must be verified with the desired safety
function. Factors which must also be considered
here include the scanning frequency, the input
circuitry and the calculated evaluation of the
SinCos signals in the controller. For this reason
the manufacturer of the controller must once
again verify the tolerance limits of the
sin²(x) + cos²(x) function.
The validity of the safety function can be scruti-
nised per increment. This means that for a reso-
lution of 2048 sine/cosine periods, the validity of
the controller can be checked 2048 times per
revolution. With a tolerance of the sin²(x) + cos²(x)
function of +/-0.5, the max. possible error path is
10% of one signal period (36° el.).
3.3 Safety Characteristics
Service life of the encoder:
20 years
PFH value:
dependent on the supply voltage of the encoder
5 V DC versions:
1.08 * 10
-8
1/h
10-30 V versions:
1.09 * 10
-8
1/h