i have a problem with the extbus device.
i have an output connected to a relay module (24v relay) and this switches a contactor but no (coolant) motor connected as yet
now on switching on using either keyboard or external button - sometimes it works but most times relay twitches off then on again- or vice versa- only sometimes staying in the correct state as shown on the mach screen.
the relay is well within current limits of the extbus and i cant see how this would affect the load on the bus.

Hi, Alan

How is the output board connected to PoKeys? Switching higher loads produces current spikes that can produce noise on other devices in vicinity. If wiring between PoKeys and PoExtBusRE board (and the board's power supply) is not properly shielded, spikes can cause the outputs to toggle.

hi
i am just using the short ribbon cable as supplied betwen the pokeys and poextbus and no shielding to the 24v supplys to and from the relay module. i have noticed that the small capacitor on the underside of the poextbus is not present- dont know if that matters?
the usb cable is a good quality shielded type

i may try disconnecting the contactor and see if that makes a difference....

also it is the open collector (poextbus) and not the poextbusre
thanks

well disconnected the contactor and all is ok now!
so may have to change  the wiring around and see how that goes!
thanks for your help.