Omron CS1G/H-CPUxx-EV1 Programming Manual page 16

Troubleshooting Problems with Unit Versions on the CX-Programmer
Problem
After the above message is displayed, a compiling
error will be displayed on the Compile Tab Page in the
Output Window.
"????" is displayed in a program transferred from the
PLC to the CX-Programmer.
xvi
Cause
An attempt was made using CX-
Programmer version 4.0 or higher
to download a program contain-
ing instructions supported only by
CPU Units Ver. 2.0 or later to a
Pre-Ver. 2.0 CPU Units.
An attempt was made using CX-
Programmer version 4.0 or higher
to download a PLC Setup con-
taining settings supported only by
CPU Units Ver. 2.0 or later (i.e.,
not set to their default values) to a
Pre-Ver. 2.0 CPU Units.
CX-Programmer version 3.3 or
lower was used to upload a pro-
gram containing instructions sup-
ported only by CPU Units Ver. 2.0
or later from a CPU Unit Ver. 2.0
or later.
Solution
Check the program or change
the CPU Unit being down-
loaded to a CPU Unit Ver. 2.0
or later.
Check the settings in the PLC
Setup or change the CPU Unit
being downloaded to a CPU
Unit Ver. 2.0 or later.
The new instructions cannot
be uploaded using CX-Pro-
grammer version 3.3 or lower.
Use CX-Programmer version
4.0 or higher.