Page 158 - Programmable Logic Controllers, Fifth Edition

Figure 7-18 Instantaneous
Hardwired relay circuit
contact instruction can be
L1 Start L2
Stop programmed using an internally
referenced relay coil.
TD
TD-1
M

TD-2
(5 s)

Ladder logic program
Inputs Internal Output
Stop Start relay
L1 L2
Stop
Motor M
Start Internal
relay Motor
M
Timer
PR: 5
TB: 1 s
Output line

Hardwired relay circuit Figure 7-19 Conveyor
warning signal circuit.
L1 Start-up Reset L2
PB1 PB2
CR
CR-1

CR-2
TD

CR-3 Horn

TD-1
(10 s)

Inputs Ladder logic program Output
PB1 PB2 TON
L1 Start-up TIMER ON DELAY L2
Timer T4:0 EN
PB1 Time base 1.0
T4:0 Preset 10 DN
Reset Accumulated 0 Horn
PB2
EN
T4:0 T4:0 Horn

DN EN

Programming Timers Chapter 7 139

pet73842_ch07_131-155.indd 139 05/11/15 4:21 PM