Now do a similar touch screen program, to read the PLC memory, there are some problems do not understand, give advice or comments please the great god!
1. The touch screen and PLC connection, is to put all the memory of the PLC to read their own? Which memory using the PLC or the touch screen which (not read) was useless to attend?
2. Made of question 1 extended out, when reading, is a region of memory should be read? Or read separately for each address?

CodePudding user response:

PLC can output data from memory, but the output format usually follow certain agreement, PLC communication generally is the modbus protocol, there are few other protocol types, the established is the modbus protocol, the specific circumstances of the modbus protocol, you can refer to national standard "application protocol modbus GBT19582.1-2008" and "GB - T1958.2-2008 modbus protocol on serial links implementation guide", understand the modbus protocol, you have to contact and PLC technology support, with their corresponding to the PLC of the modbus protocol point table, this table contains a specific data type, length, register address, etc., you can understand as the memory map, different functions, different people to write the PLC program of the corresponding point table is different, so there is no corresponding modbus protocol point table, can't do anything,

CodePudding user response:

reference 1st floor airelf response:

PLC can output data from memory, but the output format usually follow certain agreement, PLC communication generally is the modbus protocol, there are few other protocol types, the established is the modbus protocol, the specific circumstances of the modbus protocol, you can refer to national standard "application protocol modbus GBT19582.1-2008" and "GB - T1958.2-2008 modbus protocol on serial links implementation guide", understand the modbus protocol, you have to contact and PLC technology support, with their corresponding to the PLC of the modbus protocol point table, this table contains a specific data type, length, register address, etc., you can understand as the memory map, different functions, different people to write the PLC program of the corresponding point table is different, so there is no corresponding modbus protocol point table, can't do anything,

Part has been done, I can read and write the PLC memory!
The question now is:
Am I supposed to read all the PLC memory to the PC program, save the data, then use PC program which will use which? (in this case, a one-time to read a lot of data, there are a lot of it is no use!)
Which PLC or PC to use memory, then read only the PLC corresponding memory? Not all read the PLC memory! (in this case, if read by the PLC memory is discontinuous, so need a lot of reading and writing instruction!)
So want to ask, such as wei lun tong this touch screen is what to do!

CodePudding user response:

Wait for a great god reply, small white learning,

CodePudding user response:

From the application of real about it, which one should use which read, because the PLC industrial control, generally do state is indeterminate, if read ahead, probably and actual is different; If you in order to facilitate programming, of course, is a one-time all memory read more convenient, but must pay attention to the real-time status change, also can put some setting parameters of pure read out in advance, real-time state parameter is read again, and use it every time you
No particular, depends on the specific application

CodePudding user response:

Thank you very much, I am a little white, thanks to know!

CodePudding user response:

Knot, give points, thank you don't just, equal with