The factory has two identical production lines for soft sweets, one of which has been put into production and the other is still in the commissioning stage. Because of the epidemic, foreigners can’t come, so they debug by themselves, plus remote assistance.


A valve to control the flow of heat preservation water (closed pipeline), the control schematic diagram is roughly as follows. The button on the screen controls two relays, which control the opening of the valve. The valve opening is fed back to PLC and displayed on the screen. There is also a pressure gauge for flow reference.


Problem phenomenon:

When the screen opening of the two devices is the same, the pressure difference is large. Because the opening is a process parameter, the two equipments should be consistent in production.


The im151-8pn / dpcpu is used here.


Upload found that the program encryption, can not monitor, can only use a multimeter to measure whether the input of the two modules are the same. I have been exposed to voltage or current input for a long time, so I didn’t care. After measuring for a long time, I found that no matter how the opening was adjusted, the voltage and current changed too much. After checking the module, I found that it was a resistance tester. Think too much trouble, the next free monitoring software plcrecorder try, but this software only supports Ethernet.

Set channel:


Set variables:


Wave recording:

o4YBAGAP3euAYaCDAAEfIq_ Py0s037.png

Very convenient.

Then, step 7 was used again, and it was found that variables could also be monitored

Show accessible nodes:


Right click to add variable monitoring:


Add variable monitoring, the effect is the same


This method can simply assist the inspection and save the trouble and error of measuring with a multimeter.

Editor in charge: LQ

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