Installation Manual for SMX Modules - OEM Automatic AB

Installation Manual
6.6 Combination of different encoder types
For applications with encoder systems please note that, due to the implemented monitoring
features, the SMX-range does not place any particular requirements on the internal structure
of the encoder electronics, i.e. standard encoders are normally do suffice. The following
limitations do exist:
• SIN/COS encoder: The internal structure of the sensor system must be designed in
such a way, that output signals for both tracks can be generated independently from
each other and Common-Cause faults can be ruled out. Evidence of the mechanical
design, e.g. fastening of the code disc on the shaft, must also be provided. Encoders
with corresponding certificates and test reports are available in the market.
• Compact encoder with 2 x SSI or SSI + incremental: Also in this case evidence for the
absence of interaction between both internal encoder units as well as the internal
mechanical design must be provided.
• If only one encoder (e.g. compact encoder) is used, the fault exclusion "shaft
breakage / fault in the mechanical encoder connection" is required. This requires
positive connection of the encoder, e.g. by means of keyway and key or locking pin.
The SMX module detects the following faults in the external encoder system:
• Short-circuits between safety relevant signal lines
• Interruptions in safety relevant signal lines
• Stuck at 0 or 1 on one or all safety relevant signal lines
Note: See encoder types in appendix.
7 Configuration of measuring distances
7.1 General description of encoder configuration
The most important input variables for the monitoring functions of the module are safe
position, speed and acceleration. These are obtained by dual-channel generation from the
connected sensor system. A category 4 compliant architecture, i.e. continuous dual-channel
recording with high degree of diagnostic coverage, is required for Pl e acc. to EN 13849-1.
For possible single-channel components (e.g. mechanical connection of the
sensors/encoders with only one shaft/fastening) fault exclusions acc. to EN ISO 13849-2
may be used, if this should be necessary. For Pl d acc. to EN 13849-1 one may work with a
reduced degree or diagnostic coverage. Simple design sensor systems (speed monitoring
only) may under certain circumstances be sufficient under due consideration of the
permissible fault exclusions acc. to EN ISO 13849-2.
See also APPENDIX 1
Further configuration is described in the programming manual:
37350-820-01-xxF-SMX Programierhandbuch.pdf
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