nikitost

Hello everyone!   Could you help me with my problem? I have a PLC FX3G-24M and a FX3U-485ADP-MB module. I'm trying to establish connection between PLC and the Sensor to get a pressure reading. I made the program using official guides but it doesn't work... This is what it looks like:   First problem: if I set M8411 it's immediately reset. So I use the SET block. And second problem: I need to read Input Registers. The command isn't sent. I don't see the flashing light on the module and the result of command ADPRW in M8029. I tried changing the S3 parameter to 1, 8, 16... I think the problem is in the configuration. What do you think? And here is the sensor documentation. Description of input registers:   Thank you in advance if you try to help me.

Ok... it was a cable... BUT! First cable works only with Mitsubishi PLC And second works with both  The issue has been resolved 

Hello! I have a Siemens S7-1200 and CM1241 module. I use them for my pressure sensor. But I had to test the sensor on Mitsubishi PLC. Then I went back to Siemens (which I hadn't turned on for a while and didn't do anything with it). Now Siemens doesn't interact with sensor. Then I connected PLC to a PC via USB-RS485 adapter, it sends " 00 " every second. I used to work with this adapter and both PLCs and saw the correct commands. I also tried two different CM1241 modules. Can you help me determine what the problem might be?  Converter, sensor and all cables are operable. Hardware config: 9.6 kbps; Even parity; 8 bits; 1 stop bit. MB_COMM_LOAD: baud - 9600; parity - 2; Correct MB_Master_DB and CM-1241 port MB_MASTER: mode - 0; Data_addr - 30003; Data_len - 2; Data_ptr - my DWORD tag P.S.: I can't upload screens. Server return error...

dekor thank you for answer! My PC-PLC connection is ok (via Ethernet) but I'm talking about a PLC-Sensor connection. I've already set up the connection between the PLC and the Sensor before. It looks like: | Siemens S7-1200 + CM1241 | <--- 2wire RS-485 ---> | Sensor | I had a break from working with this PLC. Now that I've returned to it. And now it doesn't send the necessary commands... Previously, PLC could send command "01 04 0002 0002 D00B". And now only "00" every second. Could it be a malfunction of the PLC itself? Is there a way to check this myself?

Actually I need to read this from register D. So I found function DEMOV(TRUE, D0, MyFloatVar); It transfer bytes from D0-D1 to my variable in correct format.

Hello! I have a float number (HEX: 3CA01D0F) in Big Endian. It's 0.0195451062. I get it from the sensor and store it in a double word variable. Could you help me? How can I convert DWord to Float? If i use DFLT instruction, It treats DWord as an integer (1017126159) and just gives me 1.017126 e+009 Thanks in advance.

My colleague and I solved this problem. First, we configured the D8370 register. Then register D8420. They have similar configurations. Only a few bytes differ. The most interesting thing is that I configured CR+LF in D8370 at the end of the message, and in D8420 I had to reset this bit... But everything works and I can send and receive messages. The program is on ST, because it was more convenient for my colleague to work this way. IF LDP( TRUE, M8000) THEN     MOV( MOV( TRUE, HBC97, D8370), K2, D8379);     Start := TRUE;     MOV( MOV ( MOV ( MOV( M8411, H3097, D8420), H0001, D8421), K10, D8431), K1, D8434);      (*MODBUS: 19200, 8 bit, EVEN, 1 stop, node addr = 1, delay 10 ms *)     comm := 4;     addr1:= 2;     addr2:= 3;     S3_1 := 1;     S3_2 := 1; END_IF; IF Start  = TRUE THEN     ADPRW(ADPRW(M10, H1, comm, addr1, S3_1, D0), H1, comm, addr2, S3_2, D1);     IF LDP(TRUE, M8029) THEN         RST(TRUE, M10);     END_IF; END_IF;  

 

Ok. What I found in manual "To initiate the setup, the PLC program must use the auxiliary relay M8411 for Channel 1 or Channel 2. When the PLC program contains the "LD M8411" instruction, it is then possible to configure the MODBUS functionality using MOV operations.". In fact I did it. I remove the first line of code. What should I do next? After loading the program and restarting the PLC, nothing happens. If I use "Modify value..." function in online monitoring and set the M8411 bit, then the D8400...D8412 values will be set to the desired values, but after that M8411 will reset again and they will return to the initial values. 

Thanks for the answer! But how can I initialize the start of the configuration? If I just switch the M8411, it will turn off again, and the values will return to their initial... I need to use a local variable?