Siemens SIMATIC S7-300 Module data Product Information

Basic functions
4.1 Encoder settings
Connection of the SINAMICS S120 to the Technology CPU
Product Information, 09/2011, A5E00480378-04
97
Fine resolution (parameter 418 / Parameter 419 in the drive)
Encoders can provide much more precise information via their internal sampling mechanism
(sine / cosine oscillations, sub-sampling on a etched pane of glass). These can be evaluated
by the drive unit, and transferred to the PLC as a fine resolution.
The encoder actual values that can be transferred from the drive to the PLC are limited to
32-bit, however. If, for example, a standard multiturn encoder with a 12-bit (4096) multiturn
resolution and an 11-bit (2048) encoder resolution is used, there will be just
32-12-11 = 9 bits (512) remaining in the encoder actual value for transferring the
fine resolution.
If a greater fine resolution is to be transferred in the encoder actual value, the multiturn
resolution of the encoder actual value is reduced; although this increases the precision of the
encoder, it does reduce the encoder's absolute measuring range.
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With the technology CPU, the fine resolution for the cyclical actual value (Gn_XIST_1) is to
be set as a multiplication factor of the cyclical actual value. The factory setting of 11 bits is
correct for all standard Siemens motor encoders. It does not normally have to be changed.
The multiplication factor of the absolute actual value (Gn_XIST_2) is the fine resolution of the
absolute actual value. The factory setting of 9 bits is correct for all standard Siemens motor
encoders and does not have to be changed.
The multiplication factor of the absolute actual value is usually smaller than the multiplication
factor of the cyclical actual value, as there is more multiturn information to be transferred in
the absolute actual value (Gn_XIST_2).
If an incremental encoder is used, the absolute actual value (Gn_XIST_2) is structured
exactly as the cyclical actual value (Gn_XIST_1). The multiplication factor of the absolute
actual value (Gn_XIST_2) is then irrelevant.

Siemens SIMATIC S7-300 Module data Specifications

General

Series	S7-300
Manufacturer	Siemens
Protection Class	IP20
System	SIMATIC S7-300
Digital Inputs	Varies by module
Digital Outputs	Varies by module
Analog Inputs	Varies by module
Analog Outputs	Varies by module
Central Processing Unit	Varies by CPU model
Supply Voltage	24V DC or 120/230V AC
CPU Type	Varies (e.g., CPU 312, CPU 315, etc.)
Memory	Varies by CPU model
Communication Interfaces	MPI, PROFIBUS
Programming Languages	LAD, FBD, STL, SCL, GRAPH
Operating Temperature	0°C to 60°C
Storage Temperature	-40°C to 70°C
Relative Humidity	10% to 95% (non-condensing)