We have tape rotation services for many customers here at the datacenter. One of them does tape rotation of a specific job that only two people can verify. These jobs happen to run over night which means these guys can’t verify when we need to swap the tapes. If you don’t change the tape out quick enough the job fails, which means we have to check the tape roughly every 30 minutes all night long. That’s just madness!
This is where my newly acquired NANO-10 PLC comes in (Thanks John ;))
Nano features:
I plan on taking at length about the Nano at some point, so I don’t know that I will spend too much time on it here.
I matched this with a few products:
I mounted the LED, momentary switch, RJ45 Jack, and the PLC inside the project box:
Inside the box I: wired input one to the switch, output two to the LED, and broke out the power that was injected into the Ethernet cable and connected it to the PLC.
I then reused the aluminum bracket that was included with the project box to make a bracket for the IR sensor:
The sensor has 3 wires: 5V+, ground, and data. When the sensor detects an object the data pin syncs to ground so your input will go high. When it doesn’t detect it puts the data high. I wired this guy to input four.
Since we are using this to monitor tapes, I mounted it inline with the tapes so I can detect when either tape is ejected:
An amazing feature of the Nano is the ability to send email directly from the PLC!!!! What happens is when the sensor detects an object it sends input four high. This starts a timer. If the input stays high for 1.5 minutes then an email is generated and sent. After this an internal output is latched. This latched output prevents the email from sending any more…otherwise an email would be sent several times a second until the sensor is cleared.
I have another timer that resets the email output after 15 minutes, which means that every 15 minutes an email will be generated until the sensor is cleared.
You will also remember the momentary switch that is installed in the enclosure. This enables a 15 minute sleep mode so you can change tapes without setting the email alert off.
I also adjusted the ladder logic so that it updates a webpage on the internal web server so that you can login and see the status of the tape.
These little PLCs are amazing and the IR sensor works a treat. Any questions or comments, please drop me a comment below.
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