defcon.klaxon
Lifetime Supporting Member
Hey guys,
Well, the troubleshooting continues for the client who got hit by lightning. New CPU has been installed, and is working! That's the good news. I've got a few things to tinker with to get working properly but the CPU was definitely damaged, so replacing it was the right call. Thanks for the help in determining that.
Current issue is some of the analog input signals aren't coming back with the new CPU, however. There are a couple 1747-NI4 modules, and I'm noticing two odd things:
1. Card 1, Input 0 is flickering between 0mA and 4mA. This signal runs several hundred yards to the headworks, so in theory lightning could have damaged it. However, Input 1 on the same card is showing normal operation so it's not like the whole card is fried.
2. Card 2 has a few inputs that are reading way high values; the scale blocks show max raw value of 16834, but one of the inputs is pegged at 32767. That worries me, since max value according to the official literature is 16384. Another input is reading a bit over 20000, again beyond the scaling max value.
My question is this: if an input on one of those cards was damaged, would it result in a fault? Currently the fault light on the CPU is off. I could inject a signal into the input and see what happens, but client is over an hour away and whenever possible I try to stay remote to keep the cost down, so I don't want to drive two hours to do a five minute test if it can be avoided.
Well, the troubleshooting continues for the client who got hit by lightning. New CPU has been installed, and is working! That's the good news. I've got a few things to tinker with to get working properly but the CPU was definitely damaged, so replacing it was the right call. Thanks for the help in determining that.
Current issue is some of the analog input signals aren't coming back with the new CPU, however. There are a couple 1747-NI4 modules, and I'm noticing two odd things:
1. Card 1, Input 0 is flickering between 0mA and 4mA. This signal runs several hundred yards to the headworks, so in theory lightning could have damaged it. However, Input 1 on the same card is showing normal operation so it's not like the whole card is fried.
2. Card 2 has a few inputs that are reading way high values; the scale blocks show max raw value of 16834, but one of the inputs is pegged at 32767. That worries me, since max value according to the official literature is 16384. Another input is reading a bit over 20000, again beyond the scaling max value.
My question is this: if an input on one of those cards was damaged, would it result in a fault? Currently the fault light on the CPU is off. I could inject a signal into the input and see what happens, but client is over an hour away and whenever possible I try to stay remote to keep the cost down, so I don't want to drive two hours to do a five minute test if it can be avoided.