communication laptop to software MODSOFT 3.2


Thread Starter



I need help

The communication MODBUS from Notebook SONY VAIO ( Pentium II, 400 MHZ , Windows 98 ) to PLC MODICON 948 is not possible, the program modsoft
working ok, only no communication with PLC.

The modsoft software only displays the message " PLEASE WAIT " and the SYSTEM to HOLD, in this moment is necessary to reboot my notebook.


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I am having the same problem. It seems that there is no DTR DSR control on the newer laptops. Modsoft uses these to run flow control to the 984 Series PLC. The factory suggests using jumpers but you still have the same problem. On a Toshiba Laptop if you boot to DOS directly the serial port has these controls activated. If you have found out how to run a SONY please tell Me.
Charles M. Hicks
Richardson Logic Control
I have also had this problem, not only with Modsoft, but with Concept as well. I've seen similar problems running TISOFT with TI PLC's. Modicon tech support says that the problem is related to timing problems with Win98. (Part of the MODBUS RTU protocol requires that there be no gaps in the data transmission of greater than 3.5 character spacing. It would appear that Win98 can not do this!) Their only solution (as of a few months ago) was to use MODBUS ASCII protocol, which has no timing restraints. (This is a switch setting on most Modicon PLC's.) My solution was to DUMP Win98 and go back to Win95, which seems to work OK. Harvey
We have had this problem as well. Our new IBM laptops had a registry problem in Win98 that our IT department discovered by talking to the vendor not IBM. This problem was not limited to modsoft but other DOS based Programs that required some handshaking (protocol anylyzer found this problem) It was not a Win98 problem but a hardware specefic. A tech form another company happened to be in our shop when we were testing the new IBMs. He had an HP loaded with Win98 and it worked fine. Thats how we convinced our IT department. Another problem we had after that was bad checksum response error 120 (or something
similar). This would kick you out of online view. This was fixed by changing the dos memory properties for the icon to protected on all choices and selecting the prevent dos programs from detecting windows in the advanced properties of the icon. Hope this helps.