Rockwell Automation 2706-F11J_F11JC_F21J_F21JC DL50 INSTALLATION MANUAL - Manual (Page 84)

Chapter 6
Slave Mode Operation / Examples
6–20
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.
Figure 6.4
Ladder Diagram: Channel 0 Simplex 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 28| |
| +––––––––––––––––––+ |
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 36| |
| +––––––––––––––––––+ |
Rung 2:2
Creation of output string for DL50. Message sending is initiated by discrete
input I:001/00 and controlled by the delay timer.
First the variable is converted from an integer to an ASCII string. (AIC)
Next the output string is assembled from the separate parts. (ACN)
Finally the output string is sent out to the DL50 through CH0. (AWT)
| I:001 T4:0 +AIC–––––––––––––––––––––––––+ |
+––] [–––] [––––––––––––––––––––––––––––––––––++INTEGER TO STRING CONVERSION++–+
| 00 DN ||Source C5:0.ACC|| |
| || 36|| |
| ||Destination VARIABLE|| |
| |+––––––––––––––––––––––––––––+| |
| | +ACN––––––––––––––––––––+| |
| +–––––+STRING CONCATENATE ++ |
| | |Source A PRE_TEXT|| |
| | |Source B TEXT|| |
| | |Destination MSG_SEND|| |
| | +–––––––––––––––––––––––+| |
| | +ACN––––––––––––––––––––+| |
| +–––––+STRING CONCATENATE ++ |
| | |Source A MSG_SEND|| |
| | |Source B VARIABLE|| |
| | |Destination MSG_SEND|| |
| | +–––––––––––––––––––––––+| |
| | +ACN––––––––––––––––––––+| |
| +–––––+STRING CONCATENATE ++ |
| | |Source A MSG_SEND|| |
| | |Source B F3_F4_F5|| |
| | |Destination MSG_SEND|| |
| | +–––––––––––––––––––––––+| |