Rockwell Automation 2706-F11J_F11JC_F21J_F21JC DL50 INSTALLATION MANUAL - Manual (Page 88)

Chapter 6
Slave Mode Operation / Examples
6–24
The contents of these strings must be assigned using the PLC off-line
programming software (6200). Control code values are entered into the
strings by using a forward slash followed by two hexadecimal digits. See
Appendix B, which has hexadecimal values for all ASCII and extended
ASCII characters.
Table 6.H
Strings Representing Control Code Values for This Example
Address LEN STRING TEXT
ST12:0 19 \02\19Speed 25\FF\01\0D\80\88\80\00\00\00
ST12:1 2 25
ST12:2 2 \02\19
ST12:3 6 Speed
ST12:4 3 \FF\01\0D
ST12:5 3 \80\88\80
ST12:6 3 \00\00\00
Messages and attributes are changed by changing the strings or by having the
PLC append different pre-determined string numbers to the MSG_SEND
string. The hex values for Field 6 can be calculated using the worksheet
found in Appendix G.
Ladder Logic
The ladder logic builds a string from all the parts and sends it out to the
DL50 via channel 0. Messages sent to the DL50 by the PLC must observe
the required inter-message delays described in Table 5.F.
Note: Use a timer to avoid sending continuous messages.
Table 6.I
Ladder Diagram: Channel 0 Duplex Example
Rung 2:0
A free running timer used to trigger a variable counter and create a delay for
message timing.
| T4:0 +TON–––––––––––––––+ |
+––]/[–––––––––––––––––––––––––––––––––––––––––––––––+TIMER ON DELAY +–(EN)–+
| DN |Timer T4:0| |
| |Time base 0.01+–(DN) |
| |Preset 100| |
| |Accum 33| |
| +––––––––––––––––––+ |
Rung 2:1
A counter is used to simulate a changing variable value.
| T4:0 +CTU–––––––––––––––+ |
+––] [–––––––––––––––––––––––––––––––––––––––––––––––+COUNT UP +–(CU)–+
| DN |Counter C5:0| |
| |Preset 99+–(DN) |
| |Accum 25| |
| +––––––––––––––––––+ |