PLC Pie Guy
Member
SO I retrofitted a 4 headed filler machine a while back. It had a SLC 4 and an old off brand HMI screen that didn't work. I upgraded to a SLC5/05, used roughly the existing code with some modifications to work with my existing filler set up and away we went. I also added a new PV800 as its a cheap solution to talk to the SLC5/05 and connected it through a small 4 port unmanaged Ethernet switch.
One of the screens I made is simply an I/O screen that gives visibility to a green box if the I/O listed next to it is on. These visibility tags look directly at the Input with no buffering or conditioning whatsoever. Input on, green box is visible. This all works well for some time now.
We wanted to push the machine a little so in order to get an idea of how it was consuming air I added a small PSI transducer to the header. It goes to a 4-20MA input on CH0 of the 1 slot on my rack. None of the other channels are used. I display the PSI value on the HMI with a tag called Machine PSI that is declared to look at F8:1 as a REAL tag. F8:1 is the OUTPUT for an SCP instruction scaling the transducer input. The device is accurate and the HMI display of the value works just fine.
Here is where it gets odd.......
When this transducer is connected, the visibility controlled green boxes on my HMI screen that are associated with the discrete BOOLEAN inputs I.E. I:2.0/8 , I:2.0/9 and so on,,, are randomly changing. Even with all other I/O wiring disconnected. Also, its not lighting up the input card or turning on the inputs in the PLC, just displaying my visibility associated boxes at random. 3 of them might come on together and 1 might go off, then they might all go off and 5 of them come back on. I can also make them change by simply moving valves on the machine to make the PSI reading fluctuate. Its almost like my visibility tags are associated with the transducer value some how... but they are not!
Any thoughts on this??? Has anybody else experienced weirdness from the PV800 in such a manner???
Thanks
One of the screens I made is simply an I/O screen that gives visibility to a green box if the I/O listed next to it is on. These visibility tags look directly at the Input with no buffering or conditioning whatsoever. Input on, green box is visible. This all works well for some time now.
We wanted to push the machine a little so in order to get an idea of how it was consuming air I added a small PSI transducer to the header. It goes to a 4-20MA input on CH0 of the 1 slot on my rack. None of the other channels are used. I display the PSI value on the HMI with a tag called Machine PSI that is declared to look at F8:1 as a REAL tag. F8:1 is the OUTPUT for an SCP instruction scaling the transducer input. The device is accurate and the HMI display of the value works just fine.
Here is where it gets odd.......
When this transducer is connected, the visibility controlled green boxes on my HMI screen that are associated with the discrete BOOLEAN inputs I.E. I:2.0/8 , I:2.0/9 and so on,,, are randomly changing. Even with all other I/O wiring disconnected. Also, its not lighting up the input card or turning on the inputs in the PLC, just displaying my visibility associated boxes at random. 3 of them might come on together and 1 might go off, then they might all go off and 5 of them come back on. I can also make them change by simply moving valves on the machine to make the PSI reading fluctuate. Its almost like my visibility tags are associated with the transducer value some how... but they are not!
Any thoughts on this??? Has anybody else experienced weirdness from the PV800 in such a manner???
Thanks