[TD700] Use as Modbus Master

[user10683]

Hi,

My company bought a TD700 and we are trying to use its Modbus Master to read and write values with a Danfoss PLC (MCX).
Everything is OK I can read and write values but is it possible to create an edit field that can read an Modbus address on the danfoss PLC and write the same address ?
It seems that we need to create two variables in LogicLab one for reading and another for writing so in a edit field if I put the writing variable, if I change the setting on the danfoss PLC the writing variable is not updated

Eric

[Pixsys tecnico 1]

Hi,
assign the same LogicLab variable as input and output to the same PLC address.

[user10683]

Re,

Is it possible to request grouped modbus addresses ?

I have a lot of Modbus addresses so I need to group requests otherwise the modbus will be saturated.

Eric

[Pixsys tecnico 1]

Hi,
you can group requests only with consecutively Modbus addresses using. For example,
if you add FC-03 function, you have to insert start address, then using ADD button you can add different address to reach with the same request (see attached image)

Immagine.png

[user10683]

Hi,

OK I found how to do but I have a very BIG PROBLEM !

Modbus with a single PLC works very well but I have a big problem when 2 PLC's are connected to the same modbus network !

PLC 1 : modbus address 1
PLC 2 : modbus address 2

Modbus com : 19200 / RS485 / 8N1

Only one is working at the same time !

If I disconnect the first connector of the first PLC the second one starts to work adn vice-versa

Just a precision : my Modbus network works very well when I test with the software Modscan (I disconnect the connector on the TD700 and put it on my RS485 usb key).

I need a fast answer it is very important.

[Pixsys tecnico 1]

Hi,
I cannot see if slave devices are good because they are custom and I do not have the PCT file. However, are you sure to have set slave 1 and salve 2 with different node number and different address number? see attached picture:

Cattura.PNG

You must have MODBUS ADDRESS and NODE NUMBER equals for each PLC, so:
PLC1: MODBUS ADDRESS= 1 and NODE NUMBER =1
PLC2: MODBUS ADDRESS= 2 and NODE NUMBER =2

[user10683]

Sorry I send you a modified version my addresses are good when I test :

PLC1 : node number 1 modbus address 1
PLC2 : node number 2 modbus address 2

[Pixsys tecnico 1]

HI, send my the entire project and also your custom device file so I can check all.

You can get it there:
C:\Program Files\Pixsys PC Tools\Catalog\ModbusCustom\
it will be a file named as the device ".PCT"

[user10683]

I resend you my application test.

My PLC are now generic modbus devices but always the same issue.

[Pixsys tecnico 1]

Try with this LogicLab project

TestLogicLab.zip