15-bit encoder chip debuts at SPS in Nuremberg
With the new iC-RZ Series encoder chips from iC-Haus, safety encoders can be made even simpler and more compact. This is made possible by the innovative single-chip design as an optical twin encoder with a redundant safety channel.
The company offers the ICs for code disks with a diameter of 26.5mm for 36mm encoders or 42.5m for 58mm encoders. Prime applications are ultracompact SIL encoders for smart production environments and collaborative robots (cobots) or safety motors with integrated encoders.
The aperture is realised directly on the phased array IC. The photodiodes used are particularly sensitive to blue light. With short-wave light, higher resolutions can be achieved during the scanning process and lager tolerances simplify adjustment.
Both sensor arrays are positioned ideally on the chip base so that only one component needs to be aligned precisely with the code disk.
The double scanning process by either incident or transmitted light is performed via a control channel and a safety channel which are completely independent of each other.
This is ensured by shallow trench isolation on the chip and a separate power supply for the channels. These measures preclude Common Cause Failures (CCF).
The pseudo random code (consisting of two complementary tracks) encodes the absolute position over a word length of 10 bits. In addition, as the incremental track is read with 1024 CPR, the 5-bit on-chip interpolation of the sin/cos signals allows a total resolution of up to 15 bits to be processed.
Under laboratory conditions, the iC-RZ provides two 15-bit position words that can be transmitted using the BiSS Safety protocol, for example. In practice, 12 to 13 bits have proven to be sufficiently accurate for many safety applications.
Another high-resolution sin/cos track with 2048 CPR is scanned via an additional photodiode of the control channel.
Using the iC-MR3 for example, the analogue signal can be interpolated externally so that the iC-RZ Series is also suitable for high-resolution absolute encoders up to a maximum signal resolution of 24 bits.
The iC-RZ can also read safe multiturn information. Independent of safety applications, the encoder chip can also be used as a single-channel pseudo random code scanner for absolute position determination.
Safety encoders using the iC-RZ can be certified up to SIL 3 or PL e. The use of the single-chip solution reduces the effort required for development and certification of safety encoders to a minimum.
The high demand on redundancy can be met with just one component. iC-Haus provides manufacturers of encoders with a comprehensive “Implementation Handbook”.