SERCANS module for SERCOS II & III
The SERCOS interface has extensive mechanisms that ensure the functional capabilities of systems incorporating various manufacturers' products. A SERCOS interface master must request various data from the ring subscribers at initialization and then conducts a time slot calculation.
This complex process led to the development of the SERCANS active SERCOS interface master card, which makes the complex initialization process anonymous. The installed software initializes and manages the SERCOS interface ring by itself, streamlining the interface between the ring and motion control to a DPR interface. This in no way restricts the operating system of the control. The SERCOS interface can be used if the time grid is complied with -- this is defined by the cyclic interrupt -- and the DPR addresses and their definitions are known.
The SERCANS II module has a shared memory interface to the control unit. A version for SERCOS III is also available, and the memory interface of both versions to the control unit is compatible. Thus, the SERCANS II and SERCANS III modules are interchangeable in an application without any software modifications to the control unit. Third party drives, not just Bosch Rexroth drives, can be connected and SERCANS II/III can operate with any real-time operating system on the PC.
DRIVETOP is a user-friendly SERCANS compatible drive operating interface, which can be run under Microsoft Windows. DRIVETOP offers start-up, parameterization and diagnostics of the drives as well as securing and loading the drive parameters.
SoftSERCANS for SERCOS II
What SoftSERCANS Is
SoftSERCANS is a software interface master function to SERCOS-based
drives*, which runs on the Ardence (formerly VenturCom) RTX real-time Windows software. SoftSERCANS is a SERCOS interface driver to PC-based soft motion control, just as printer drivers are for a PC. With SoftSERCANS, the SERCOS interface accomplishes the complete unbundling of software and hardware.
The object code of SoftSERCANS Version 1.0 is downloadable from this site at no charge, making it easier and cheaper for CNC and motion control manufacturers to incorporate the fiber-optic SERCOS interface into softCNC or soft motion control products. SoftSERCANS Version 2.0 is developed and supported by Bosch Rexroth, and is available from that firm.
* Note that SoftSERCANS is intended to control servo drives of any manufacturer, provided those drives have passed the SERCOS interface conformance test.
SoftSERCANS initializes the SERCOS loop and manages the data communication on the loop, managing all SERCOS services such as real time data communication, service channel, and diagnostics. A real-time software (e.g., soft-CNC) based on
Ardence's (formerly VenturCom) RTX establishes the communication with SoftSERCANS via DLL. Features of SERCOS allow SoftSERCANS to make Realtime Windows® a hard deterministic motion control platform. SoftSERCANS enables Realtime Windows to perform read and write functions within a relatively large time frame, designed by the time slot configuration to compensate for jitter. The SERCOS internal clock and the synchronization mechanism establish a rigid sub-microsecond time lattice, giving the data communication within the SERCOS loop the determinism necessary to satisfy the highest requirements of
today's servo drive technology.
SoftSERCANS allows the internal mechanisms of SERCOS to remain a black box to motion control development engineers. The only hardware requirement is a passive SERCOS card, presently available from Automata, Bosch Rexroth and Hilscher for approximately $250.
What SoftSERCANS Is Not
SoftSERCANS is an important software component of a SoftCNC or SoftMotion Control, but it is not a complete control package that can be used as a stand-alone product. The SoftCNC/SoftMotion developer must still create his HMI and application packages, using SoftSERCANS to provide the black box interface to SERCOS interface drives and SERCOS interface I/O devices.
SoftSERCANS was written in C++. The SoftCNC/SoftMotion developer should be familiar with C++ and Windows programming, have experience with realtime applications and have a basic familiarity with the SERCOS interface.
Download SoftSERCANS Version 1.0 at No Charge
The software is downloadable at no charge from this website (download
here). The SoftSERCANS V1.0 technical manual can also be downloaded at no charge.
Performance
SoftSERCANS is designed to support a maximum of 40 axes and a minimum SERCOS cycle time of 500 µs. A lab test shows that SoftSERCANS can support 8 axes with a typical telegram configuration for machine tool with a cycle time of 1 ms, when a 200 MHz Pentium and 4 Mbps data transfer rate are used, while consuming less than 10% of the CPU’s resources.
Because SoftSERCANS is software only, its performance improves as hardware performance improves. It checks and dynamically adapts to the performance of the processor during installation. Utilizing the SERCON816 ASIC and increasing the speed of the processor will further expand performance and the number of axes supported for a given cycle time.
Determinism of the system is assured by the mechanism of SERCOS, which is independent of the data transfer speed and ensures sub-microsecond synchronization accuracy of all axes in the system.
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Microsoft Windows NT V4.0**
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Min. 32 MB of RAM (64 MB recommended)
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Ardence RTX 4.3 or higher
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Recommended: Microsoft Visual C++ version 6.0 or higher.
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Recommended: Debugger Numega Softice version 4.05 or higher
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Test program SoftSERCANSTest from V1.0 -- aid to check functions of SoftSERCANS without real-time accessing (is automatically installed when installing SoftSERCANS).
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PC motherboards of the most recent generation (Pentium II or higher)
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PC plug-in card
-- Cards are available from Bosch Rexroth, Automata and Hilscher
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** RTX and SoftSERCANS operate with Windows 2000 and XP.
They are not supported for Windows 95, 98 and ME.
Field experience
The SoftSERCANS function structure is a software representation of the hardware version of SERCANS, which is an active SERCOS master card introduced in 1996. More than 70 companies worldwide have proven the functions of the SERCANS card in the field. The original SERCANS offers a DPR address where the controller reads and writes data within a predetermined time frame initiated by an interrupt signal. SoftSERCANS offers a larger comfort factor by employing a DLL.
Applications employing SoftSERCANS have been operating in production environments since January 2000.
Support
SoftSERCANS Version 2.0 is supported by Bosch Rexroth, only when used with products that have passed the
SERCOS Conformance
Test.
This is important because non-certified products that claim to be SERCOS interface compatible may have conformance problems, something which does not necessarily have anything to do with SoftSERCANS. These problems can then often be eliminated once the product passes the conformance test.
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