Rockwell Automation 1785-Vx0B, D17856.5.9 PLC-5 VME VMEbus Programmable Controllers User Manual - Manual (Page 20)

Chapter 1
Overview
1-9
Ladder programs from a standard PLC-5 processor run in the PLC-5/VME
processor. The PLC-5/VME processor has the same program scan time as
the PLC-5 processor. The PLC-5/VME processor has the same extended
instruction set as the PLC-5 processor.
Features of the PLC-5 processor not present in the PLC-5/VME
processor are:
PIIs
EEPROM memory module
logical rack 0 (128 less I/O points)
Features of the PLC-5/VME processor not present in the PLC-5
processor are:
The PLC-5/VME processor defines a special data file called the “VME
status file.” This file gives ladder programs the ability to control and
monitor certain VMEbus state information.
The ladder MSG instruction is extended to allow ladder programs to
perform VMEbus data transfers and generate VMEbus interrupts.
Finally, features present in both but implemented or represented
differently are:
The serial port (channel 0) on the PLC-5/VME processor is RS-232C
only (not configurable for RS-422 and RS-423).
Different batteries are used (cat. no. 1770-XYV).
The PLC-5/VME processor has a memory-protect switch. In the PLC-5
processor, the equivalent switch is on the 1771 I/O rack.
The PLC-5/VME processor retains a significant amount of compatibility
with the 6008-LTV processor. This eases the task of converting 6008-LTV
ladder programs and CPU driver programs to use with the PLC-5/VME
processor.
6008-LTV ladder programs may need editing because the VME status file
in the PLC-5/VME processor is different in several ways from 6008-LTV
status file. The 6008-LTV ladder programs that access the VME status file
will need to be changed.
Compatibility with the
Standard PLC-5 Processor
Compatibility with the
6008-LTV Processor