Mitsubishi FX2N Analog Output - huh??

  • Thread starter Jody Gallant CET
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Jody Gallant CET

We just purchased a Mitsubishi FX2N PLC for a project we are working on. The project requires an analog output (0-10V) so we purchased the FX2N-2DA 2 channel Analog output card. Does anybody have any experience with these? The logic to output a value seems quite complex. I have done Analog output on AB and Modicon equipment and it was just a simple MOV command into the proper output register, however with this unit it requires a communications call to the "special functions unit". The sample in the documentation is very vague, and doesn't go into detail. Can anybody help me out????? Thanks Jody Gallant CET

Pierre Desrochers

You are exact when you say the setup is complicated... First you must "write" the settings to some buffers... telling the module how to function. You must setup the number of channels, the range, etc. To do this you use "TO" instructions and once it is done you just write or MOV the data to the specific registers. Start with buffer # 1 and work your way up to the last one... I think its # 29... One good way to do it is to look at the example at the end of the booklet... copy the same example and try it out... Be carefull that some buffer memory are not explain in a continuous way in there books... you will find some stuff at the beginning of the book where the next step would be written at the end... Pierre Desrochers [email protected]

Colin Carpenter (UK)

Jody, To get the FX2DA running simply, all you need to do is programme the following lines: LD M8002 (first run pls) TO (Mitsubishi command) K0 (means special unit 0- use if you only have one special unit) K0 (Special unit Buffer Memory #0) H00 (Means you're setting both channels to voltage outputs) = K1 (Number of words to write) That will configure the unit so that both channels are voltage output every time the programme "first runs". Bit values of 0-2000 will be equal to 0-10volts. Now you need to send values to the outputs. To do this, write the following lines. LD M8000 (always ON flag) TO (Mitsubishi command) K0 (Special unit 0) K1 (Buffer Memory 1 of special unit (start address)) D0 (Start register of D0) K2 (Number of words =3D 2) The above lines will write the values stored in registers D0 and D1 onto buffer memories #1 (channel 1) and #2 (channel 2) of special unit 0. Obviously, if you want different data registers, then just change the D values. That's it in a nutshell. You can get pretty sophisticated with other checks, restrictions etc, but the above lines are probably all you really need. Cheers, Colin Carpenter, TCS Automation, UK