50/​60 Hz ripp­le when the tes­ter is connected

The CAN-Bus Tes­ter 2 cau­ses a ripp­le fre­quen­cy on the bus at mains fre­quen­cy (50 or 60 Hz) when used with the included power supply.
The pro­blem is con­cept indu­ced, con­cerns all swit­ching power sup­pli­es and is defi­ned by the para­si­tic capa­ci­ty bet­ween mains- and secon­da­ry side of the cir­cuit. That’s the reason for a small ripp­le on the bus. Depen­ding on how many nodes are on the bus and how their inputs are wired, the phe­no­me­non is seen more or less.
Usual­ly, this makes no trou­ble. Only on a bus with very few nodes and a high poten­ti­al dif­fe­rence (com­mon mode) an inter­fe­rence is theo­re­ti­cal­ly possible.
Pos­si­bi­li­ties for cor­rec­ti­ve actions:
  1. If your bus sup­pli­es vol­ta­ges, then try to run the tes­ter from the bus and remo­ve the tes­ters power sup­p­ly. The tes­ter works fine with bus vol­ta­ges from 9V.
  2. Sup­p­ly your tes­ter from a bat­tery, a rech­ar­geable power bank or the like.
  3. Con­nect the ground of the power sup­p­ly to the ground-poten­ti­al of your bus. The­r­e­fo­re you would need an adap­ter or you open the dc-cable or dc-plug of the power supply.
  4. For the wiring test a sup­p­ly vol­ta­ge of 24V is requi­red. Plea­se note this for bat­tery operation.

    50 Hz ripp­le over­lay­ed to CAN-messages
    Ope­ra­ti­on with ground-con­nec­tion to bus-ground-potential

    Ope­ra­ti­on with battery-pack

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Article last edited on Article first published on
2019/​06/​28 2017/​01/​03