Rockwell Automation 1785-BCM_BEM, D17856.5.4 PLC-5 Backup Communication Module User Manual - Manual (Page 152)

Reference Information
Appendix B
B-5
Use Table B.A and Table B.B to estimate your data table transfer times.
These tables provide tested values that are derived from method 1 and
method 2 sample applications programs provided in Appendix A.
Table B.A
Data Table Typical Transfer Time Using Method 1 Program
with Minimal Program Scan (3–8 ms)
Number of Blocks
Being Transferred Number of Words
Being Transferred
Transfer Time (in ms)
for Series A BCM
(see notes 1 & 2) Transfer Time (in ms)
for Series B BCM
Fast Transfer Mode
Enabled (see notes 1,
3, & 4)
1 62 230 40–110
3 186 330–820 50–120
7 434 440–1500 50–160
10 620 1100–1700 60–210
16 992 1900–3300 140–280
1 These times can significantly change based on program scan. But an increase in the number of
blocks does not significantly affect program scan.
2 Times were taken using a PLC-5/25 processor.
3 Series B BCM module with fast mode disabled is roughly double the times shown.
4 Times were taken using a PLC-5/40 processor with one channel configured for DH+ and three
channels configured for remote I/O scanner at 230 kbaud.
Determining Data Table
Transfer Time