Rockwell Automation D64046.5.1 U MNL WIN DDMC - Manual (Page 149)

Reference Information
Appendix A
A-5
Maximum Number of Steps per SDS Instruction
Tables A.G and A.H list the number of steps you can enter per SDS
instruction in the PLC-5 and PLC-5/250 depending on the number of I/O
you have.
Table A.G
Number of Steps Per SDS Instruction in the PLC-5
If you have this number of I/O: Then you can enter this number of
steps per SDS instruction:
8 76
16 45
32 23
Table A.H
Number of Steps Per SDS Instruction in the PLC-5/250
If you have this number of I/O: Then you can enter this number of
steps per SDS instruction:
8 250
16 250
32 232
Loading Considerations for Multiple PLC-5 Configuration
The DDMC32 system does not limit the number of PLC-5s you can link to
the operator interface. However, to maximize performance of the Data
Highway Plus, we recommend that you have no more than 20 PLC-5s
linked to one Data Highway Plus.
Your messages do not get lost when using multiple PLC-5s; they are,
however, read on a first-in basis.