FX3U & IEC DEVELOPER

[BenJones 1]

Hello guys, Hope everyone is well. I'm about to set up an FX3U as I've shown (Attachment 1). (Qu.1) Is it possible to use one channel only as both a master and slave or do I need 2 channels : one to use as a master and one to use as a slave ? (Qu.2) To setup 2 channels I shall do the following. I will be using a CNV_BD card as an expansion port which shouldn't allocate a channel. Then 2 x RS485 ADP cards which will be allocated as CH1 and CH2. I wish to use channel 1 as a Modbus Master and channel 2 also as a Modbus Master. I realise that you cannot allocate both cards (CH1 and CH2) for use with modbus protocol (attachment 2), because if b0 in 8401 and 8421 are both high then priority will be taken with CH1 and the PLC cannot read from CH2. I think that there is a 'work around' for this as Kaare mentioned before and mitsubishi have programmedi a program for this in their modbus soluton pack ? I see that Beijer / Mitsubishi have programmed ADP Modbus function blocks for Ch1 and CH2, so I would think you can use them together, right ? I have the 'FX modBUS solution pack' from Beijer (Attachment 3), but I don't know which are the most appropriate function blocks to use for CH1 and CH2. Can anyone shed some light on this ? Do I use : Channel1 (ADP): ModbusFX3UMaster_V100.zip Channel2 (ADP): ModbusFX3UMasterADP_MB_V100.zip ? If so, which function blocks / programs should I use from each that will work ? Remember, both channels should read modbus protocol. Do I use : ModbusFX3UMasterRS2_CH1 for channel 1, and ModbusFX3UMasterRS2_CH2 for channel 2, or ModbusFX3UMasterRS2_CH1 for channel 1, and ModbusFX3UMasterADP_CH2 for channel 2, or What will work ? Also, please, what does ADP mean and what does RS2 mean ? Kaare, you said previously, that : "Mitsubishi/Beijer have written the Modbus protocol in pure code so that both channels can be used at the same time (one of the cards is configured using the "built-in" Modbus protocol, and the other card uses the programmed Modbus protocol)." Which is which ? Many thanks for any help, Ben Edited 11 Mar 2011 by BenJones

[kaare_t 155]

You can do that. The function block containing "ADP" is the one that uses the built-in protocol structure while all others are pure code function blocks.

[BenJones 1]

Thanks ! I got it working Ben