FM351 chanel synchronisation lost

[JG73 0]

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

[Mike Dyble 0]

Surely you should use the Jog mode to move the axis, in this way the FM351 would not get 'confused'. I had a quick look at the manual and it seem as if it is fairly easy to do

[JG73 0]

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