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:
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- 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.
- Supply your tester from a battery, a rechargeable power bank or the like.
- 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.
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