JG73

1_Slave_multi_read.zip Hello, I have Premium unity PLC using READ_VAR and WRITE_VAR blocks to read and write datas in a distant non Schneider PLC. I have only 1 slave but I use 3 READ blocks and 1 WRITE block in order to read words and booleans datas at different adress in the slave memory. My ladder program is close to what you have done, the only difference is that I don't use a timer to increase my block pointer value but the falling edge of the running block activity bit. Since the beginning I'm facing the following problem. The two PLC's exchange a life bit. If this one is steady for more than 20 seconds a fault is raised up. Unfortunately this appens regularly. The PLCs are distant from about 2 Kilometers but we are using a fiber optic network. Obviously the communication should be faster than what we have. Any suggest is welcome. I join the ladder program for the communication task (Hope that you can understand my english) Best regards

Thanks Mike! We finally found the answer to our synchronisation losing problem. It wasn't due to the movement done without use of the FM351 but caused by electrical perturbation on the coder signal each time we switch off the solenoid of the electrovalve used to do it. We made several test and finally see that each solenoid of the valves mounted on the manipulator generate short loose of signal on the coder. We solved the problem by adding free-wheel diode on each solenoid. We now have less problem... it's still appening but we thing that's cause by the other valve wich aren't not on the manipulator. So we have to had diode everywhere. Thanks

Hi all; I'm working on a two axis manipulator and so use a FM 351 module for manipulator movement control horizontaly and verticaly. I'm no facing the following problem. During my process I should move down my manipulator in low speed for few second. To do so I don't use the FM351 to do this movement but an other output on the PLC. So the FM351 is not inform that the manipulator is moving down by action of the PLC. During this movement I get fault on the concerned channel but this seems to be normal because the manipulator is getting out of the last destination area he reached. The problem is that at the end of the movement I loose the synchronisation of the concerned channel and only at the end of the movement. I really don't understand why nothing occur during movement and why I loose the synchronisation. Does anyone have experience on this module or allready face this problem? Help is needed quickly.....I now commissioning the manipulator. Thanks JG73