884 Online Software


Thread Starter

Steve Shelton

I am working with a site which has about 100 884 PLCs (yes, that's PLCs, not I/O), and has, as its only programming tool the old Taylor Online software. We are trying to set them up so they can program from Windows based PCs, using a command console (DOS box). Generally, this works, however, we routinely get COM port timeouts, protocol errors, poll errors, and overrun errors. We have tried using Window98 and NT 4.0, with marginal success at getting rid of the problems.

I am looking for any connection to someone who knows this software and can tell me what the errors mean, or who knows what to do about them.


Bruce Durdle

A common problem that can arise is that the RTU form of Modbus is sensitive to message timing, whereas the ASSCII form is not If you can change your PLCs and software to use ASCII it is usually a lot more reliable.

I have experienced this with other DOS based software. Other PLC Software particularly DOS based Sucosoft for Moeller PLCS. The DOS Software want exclusive access to the comm port and needs to run all the time not in a time slice on a multitasking system. Running these programs in real DOS , has always solve the problem. In DOS mode for Windows 95 there is an option to prevent the program from knowing its running under windows. This improves it but by no means cures it. Running at lower baud rates also seems to help. Timing seems to be critical, I guess it has to do with the amount of data buffered in the UART and associated hardware. We run Taylor online form a fat16 partition on a notebook set up as dual boot to support one PLC for a customer.


Craig Smith

Joseph Luft, FasTrak SoftWorks, Inc.


FasTrak SoftWorks sells and supports a programming package for the Modicon 884 processors. We have been using it on various Windows platforms with some success. If you would like to contact me, we'll see what we can do for you.

Thanks. Joe
FasTrak SoftWorks, Inc

[email protected]