Modicon PLC 984-145 and Communications

J

Thread Starter

jb

In order to remotely talk via modem to a modicon 984-145 CPU, I feel it is necessary to change the memory settings for the communication parameters from RTU to ASCII.
The default parameters are RTU, 8, even, 1 and are used when the switch on the front of the CPU is in position DEF.

The 'supposedly' writable communication parameters are used when the switch position is in position MEM.
Who do I write my required ASCII settings to the memory on the CPU??

Any suggestions??
 
In the PLC configuration part of modsoft (or proworx), there's a topic to set modbus communication ports bauds, parity, etc... After you change them to ASCII,7,etc..., you just download your program to the PLC (connecting at RTU,9600,8,E,1) and after the PLC restart, the "memory" position of the switch will aply your downloaded modbus port settings. Try first to reconnect to the PLC using new settings, then have fun with your modems, i had good result with modems using ASCII,9600,7,E,1. Good luck!

 
Thanks for the advice, spot on. Worked a treat.

One more query...
Using modsoft I see 2 port settings available under the Config / Ports topic.
i.e. Modbus 01 which has been setup as ASCII,7,e,1 for modem connection to the modbus port
and...
Modbus 02 setup as RTU,8,e,1 [default modbus settings]
What does modbus 02 relate to??
 
Hi There,

I'm back again with another query on the above.
In the modsoft topic Config, Ports, there are 2 selections i.e. Modbus01 and Modbus02.
What do these relate to??
Are they the MEM settings relevant to modbus numbers 01 and 02 of the PLC i'm connected to?
Does this mean I can't download ASCII settings for a PLC with modbus address 12??
 
You probably have 2 serial modbus ports on the PLC, which you can configure the way you want them (including the modbus address you want, that can be different for both ports). What you have to know is the actual settings of at least one port of the PLC before you change them offline in Modsoft config. You will use these settings (into Modsoft PLC address) to download the new ones to the PLC, put the switch in MEM mode and put back the PLC in run. You can then use "Direct connect" to verify that the new port settings are still fonctionnal on both ports.
 
Thanks for the tips.
I've sorted the comms issue now.
Just another query on modicon if you don't mind.

I've a simple h/w config consisting of a 984-A145 CPU, 1 number DAP216 and 1 number DEP216. The application is programmed using cmodsoft.

I'm experiencing a stop code error 0010H when i allocate the dap216 module to a particular slot using the s/ware i/o map.

However, the cpu will go into run OK if the dap216 card is positioned elsewhere in the rack , in a slot defined as some other module.

The cpu will also go into run if the i/o map does not reference the position of the dap216 card.
Any help will be appreciated

thanks
jb
 
Concerning the DAP16 card, you may need to add a "loadable" to that card in the configuration so it will be downloaded to the PLC for supporting the card! (reed carefully the card install manual).
 
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