!! Warning !! WDT Watchdog 5V 2 Pin screw Plug Reverse Polarity

T

TonyD

Member
Hi Alex
I would like to bring to your attention that the 5Volt 2 pin screw connector mounted on the WDT Watchdog card is reversed polarity as compared to the same 5V 2 pin screw connector plug connector mounted on all other Sequent cards. It appears that all sequent cards follow the same polarity for this 2 pin screw connector except for the WDT UPS card.

I found this out the hard way by releasing the magic smoke from some of the components on the 16 LV digital input card when i re powered the Sequent Cards & RPI after using the same plug & cable that was used to supply power to WDT card & live system.
The Live system needed to be powered while the WDT UPS card was removed & it seemed the logical course of action was to supply power to the last card in the stack which was the 16 LV Digital Card.

I will be ordering a new 16LV Digital card & spare when they are available along with some additional cards & RTD sensors.
Will need to order some spare cards & such to hold onsite so as not to unduly affect operation in Australia when failures

Further Visual investigation of all Sequent cards i have confirmed this reversed polarity on the WDT UPS Card
for your information The WDT Card was removed for testing of the interrupt issue away from the live system

Am just bringing this to your attention that if you are ever redesigning the WDT UPS card you may want to review this error & change the polarity to the same as all other sequent cards to prevent mishaps by other users.

Love your cards Excellent work & the excellent service you & your company provide.

Regards TonyD
 
alexburcea

alexburcea

Moderator
Staff member
Hi Tony,

I am sorry to hear you burn a card. This polarity error was inherited from the older versions of the watchdog and we were reluctant to change it because of the retro compatibility. One feature that could prevent the burn but we start removing from all our cards is the reverse polarity protection. The reason for that is that there is a significative voltage dropout on the circuit especially for high current demanding systems (rpi5 especially).
The new run of production for 16-LV Digital inputs card is on the way to the final assembly and testing facility and will be available in about two weeks. The new card has been redesigned, replacing the I/OExpander with a microcontroller. The card firmware will be (in the system) updatable from Raspberry PI so any possible bugs can be easily corrected.

Alex.
 
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