Function Parameters - Incremental Encoders - Siemens SIMATIC S7-300 Manual

Description of Functions
Function Table 9-9 shows you how to adapt the selected encoder to the
parameters
FM 354.
Table 9-9
10
11
12
13
19.0
20
20.0
20.2
20.3
MSR stands for measurement system raster (see Section 5.3.1)
Sample encoder Encoder: Number of increments per revolution (MD13) = 2,500
adjustment
(The FM 354 works by the principle of quadruple evaluation. This yields an
FM-internal number of increments per revolution = 10,000.)
Machine design:
From this one can calculate the following traversing distance per encoder
revolution:
Gear ratio: i =
Displacement per
encoder revolution =
The following values are entered:
9-62
Function parameters – Incremental encoders
MD Designation
Encoder type 1 = Incremental encoder
Displacement per 1...1 000 000 000
encoder revolution see Section 5.3.1, Dependencies
(division period)
Residual distance 0...2
per encoder revo- see Section 5.3.1, Dependencies
lution (division pe-
riod)
1
Increments per en- 2 ...2
coder revolution see Section 5.3.1, Dependencies
(division period)
Direction adjust- 1 = invert measured value direc-
ment tion
Hardware monitor-
ing
1 = Cable break
1 = Pulse monitoring
1 = Voltage monitoring
Motor with 50:30 gear ratio on spindle with 10 mm pitch = 10,000 MSR
Encoder on motor.
MD
11
32
12 0.666... 2
13
Value/Meaning
32
–1
25
50 spindle revolutions
= 1.666666...
30 motor revolutions
i 10,000 MSR = 16,666.666... MSR
Value
16 666
= 2,863,311,530 (2
2 500
FM 354 Servo Drive Positioning Module
Comments/Unit
(Code number)
(MSR)
(integer portion)
–32
(2 MSR)
(fractional portion)
Entry according to
encoder rating plate
–
Entry for monitor-
ing to be switched
on
Unit
–3
(10 mm)
–32 –3
10 mm)
(puls/rev)