December 10, 2020

Danger when using incorrect residual current devices (RCD / RCCB) in domestic electrical installations. 

Residual current circuit breakers (RCCB) switch off the power supply when dangerously high residual currents occur. In this way, they protect people, animals and installations.

Many electrical installations in buildings were built with standard RCD / RCCB type A. 
Since many buildings today also have frequency converter/inverter drives (e.g. in treadmill ergometers, lifts, heat pumps, heaters, washing machines, tumble dryers, air-conditioning systems, ventilation systems, etc.), the standard RCD / RCCB type A often are no longer sufficient.

The RCD / RCCB must therefore also be universal current sensitive in such buildings / rooms, because the leakage currents of a frequency converter have, in addition to alternating current, a considerable direct current component or smooth direct fault current. High-frequency leakage currents with high amplitude can also occur in frequency inverters with EMC filters and long shielded motor supply cables.
In the case of a mixed form (smooth DC residual current superimposed by AC residual current), the AC residual current can only be transmitted weakened or not at all, since the iron core is partially to completely premagnetised by the smooth DC residual current.
If the right RCD / RCCB is selected, one of its functions is to interrupt the circuit if a person suffers an electric shock, e.g. due to insulation damage to a cable, because a sensitive RCD / RCCB then recognises this "residual current" as a "residual current".

In extreme cases, if an incorrectly selected RCD / RCCB is used and, for example, frequency converter drives of the above-mentioned devices are operated at the same time, a standard RCD / RCCB of type A may not trip in the event of an error. Therefore, in the worst case, there may also be a danger to human life.

Please also observe DIN VDE 0100-530 ("Setup of low-voltage installations - Part 530: Setup and installation of equipment - Switchgear and controlgear") which requires type B residual current devices in certain installations.

h/p/cosmos recommends RCD / RCCB of type B for the relevant building installation when using running belts with frequency converters.

RCD / RCCB of type B are all-current sensitive. They protect against pulsating and alternating residual currents, residual currents with mixed frequencies and smooth DC residual currents at frequencies up to 150 kHz.

h/p/cosmos recommends RCD / RCCB types B of the manufacturers: Doepke or SIEMENS

There are a few RCD / RCCB types B which trip too early ("over-sensitive") during operation with frequency inverter drives when the device is not equipped with a potential-isolation transformer. In such a case you can either install a differeht RCD / RCCB Type B in your domestic building installation or alternatively you can  retrofit a special leakage current reduction filter into your h/p/cosmos treadmill: Article order number of the leakage current reduction filter: cos103565-01ret

Further information can also be found on the websites or operating instructions of corresponding manufacturers or in technical literature.


February 8, 2019

Safety warning for the old coscom v1 and coscom v2 interface protocols:

In the very old coscom v1 and coscom v2 interface protocols the command of a negative speed (e.g. -0.5 km/h) can lead to unwanted acceleration.
Do not send negative speed commands via RS232 interface when working with coscom v1 or coscom v2. Upgrade to coscom v3 or coscom v4 as soon as possible!

coscom v1 and coscom v2 will be deleted automatically from the MicroControllerUnits MCU5 during the next Firmware Update of the treadmill.
MCU6 never included coscom v1, v2 or v3.
MCU4 controllers (build from 1997 until 2007) cannot be updated but can be upgraded with MCU5 including coscom v3 and coscom v4.
For MCU1, MCU2 and MCU3 controller in UserTerminals (build from 1988 until 2001) no updates or upgrades are available.

Important update from coscom v3 to coscom v4:

From January 2019 please use coscom v4 for control of h/p/cosmos and relevant OEM treadmills.
coscom v3 is still a very safe protocol and remains supported at this stage.

However, coscom v4 has additional safety features (initial re-confirming of treadmill start, compulsory failsafe instead of optional, etc.) and includes basically all essential commands required for treadmill control.
coscom v3 and coscom v4 are not fully compatible due to different structures.
coscom v3 still remains active for updating treadmill MCU5 firmware and also for implementation of functions such as keyboard and LED simulations, MCU5 optional functions, etc.

A description of coscom v4 please download here:

End of support for older coscom.dll (v1 and v2)
The support for all older coscom® files (including coscomekg.dll version 1.00 and coscom.dll version 1.2.9 and also including coscom v2) ended on 31.12.2010 as announced earlier in 2010.

Please upgrade in time to the new coscom v3 .NET Objects and coscom v3 .NET Controls or better to the latest coscom v4.

Please note also, that the older versions of coscom v1 and coscom v2 are not designed and not documented based on IEC 62304 (Medical device software - Software life cycle processes) and ISO 14971 (Medical devices - Application of risk management to medical devices).

Therefore from March 21, 2010 it is obligatory to upgrade to h/p/cosmos coscom v3 or coscom v4 in order to stay compatible with the latest norms, latest safety standards and Regulatory Affair Issues when connecting to h/p/cosmos medical treadmills.

The safety of all users and operators, ensured by 100% function, performance, quality and safety of our products, is our top priority. Therefore we forward field safety notices, information and warning letters to our customers and service partners even for cases, where the probability of a defect and the severity of a possible injury may be extremely low.

Field safety notice to buckle (fastener) of
h/p/cosmos safety harness chest belt

Warning message 20.02.2016

Field safety notice to ripcords
for treadmills built in 2014/2015

Warning message 10.12.2015

Field safety notice to a safety update for
the MCU5 to update the firmware to v1.02.2

Warning message 10.12.2007

Field safety notice to the
chest belt of the h/p/cosmos safety arch

Warning message 11.03.2005