PG DRIVES TECHNOLOGY S-DRIVE – APPENDIX - A
SK76745/10
Annex — S-Drive command signal leakage
1 Introduction
It is possible for S-Drive installations to meet the command signal leakage requirements of ISO 7176-14:2008.
To meet the requirements it is necessary to do the following:
1) define limitations for the configuration of the throttle circuitry;
2) define specifications for the throttle potentiometer;
3) specify minimum values for the deadband setting;
4) extend the installation instructions to manage leakage risk.
It is assumed no active circuitry (e.g. amplifiers) is used in the command signal path. If active circuitry is included, or there are
other deviations from these instructions, responsibility for the installation meeting the command signal leakage path requirements
rests entirely with the scooter manufacturer.
2 Input circuit configuration
Any of the normal input configurations, single-ended, wig-wag or unipolar, may be used.
It is essential that series-connected speed-limiting potentiometer and ISO-test resistor are NOT fitted. A parallel speed-limiting
potentiometer may be used.
3 Potentiometer specifications
3.1 Wig-wag/unipolar throttle
At initial installation:
Track resistance 5.0 kilohm ± 20 %
Wiper contact resistance less than 100 ohm
Centring tolerance (electrical) 50 % ± 2.5 %
At end of service life:
Track resistance 5.0 kilohm ± 20 %
Wiper contact resistance less than 100 ohm
Centring tolerance (electrical) 50 % ± 3.5 %
3.2 Single-ended throttle
At initial installation:
Track resistance 5.0 kilohm ± 20 %
Wiper contact resistance less than 100 ohm
End-point tolerance (electrical) less than 3 %
At end of service life:
Track resistance 5.0 kilohm ± 20 %
Wiper contact resistance less than 100 ohm
End-point tolerance (electrical) less than 5 %
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