Allen-Bradley ClutchBrake PLC-5 Series - Page 85

4–23Write Ladder Logic
Publication 65566.5.1 - October 1996
The time required to execute the example STI program (Figure 4.27)
is about 1/2 ms, so we suggest an STI interrupt interval of about 2
ms. The shorter you make the STI interrupt interval to increase the
accuracy of the brake monitor, the less time remains to execute the
main program so its overall execution time increases.
The program uses the following words:
Address Description
N91:1 last brake time
N91:3 last brake angle
N91:4 starting brake angle
N91:5 final brake angle
N91:6 STI count for brake time
N91:7 STI count for no angle change
N91:8 resolver angle change
Figure 4.27
Example
Brake Monitor Program
Rung 9:8
| First Scan Last |
| Bit Brake Time |
| S:1 +CLR–––––––––––––––+ |
|––––] [––––––––––––––––––––––––––––––––––––––––––––––+–+CLEAR +–+–|
| 15 | |Dest N91:1| | |
| | | 0| | |
| | +––––––––––––––––––+ | |
| | Last | |
| | Brake Angle | |
| | +FLL–––––––––––––––+ | |
| +–+FILL FILE +–+ |
| |Source 0| |
| |Dest #N91:3| |
| |Length 5| |
| +––––––––––––––––––+ |
Rung 9:9
| C/B Dual Valves| Looking For |
| Engaged | Zero Speed |
| B160 B90 |
|––––] [–––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––(L)–––––|
| 170 32 |
Rung 9:10
| Looking For C/B Dual Valves |
| Zero Speed Engaged |
| B90 B160 B90 |
|––––] [–––––+––––]/[–––––+–––––––––––––––––––––––––––––––––––––––––––––––( )––|
| 32 | 170 | 34 |
| | Clutch A | |
| | Feedback | |
| | I:6 | |
| +––––]/[–––––+ |
| 0 |
Rung 9:11
| Get the |
| Speed and Angle |
| B90 I:001 |
|––][––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––––(IIN)–+–|
| 34 |