Delta Electronics Programmable Logic Controller DVP-PLC - Manual (Page 188)

4 Step Ladder Instructions
DVP-PLC Application Manual 4-18
Program Example 1:
1. Use of IST instruction
M1000
IST X10 S20 S60
S X10: Individual operation
X11: Zero return
X12: Step operation
X13: One cycle operation
X14: Continuous operation
X15: Zero return enabled switch
X16: Start switch
X17: Stop switch
2. When IST instruction is being executed, the following special auxiliary relays will switch automatically.
M1040: Operation forbidden
M1041: Operation starts
M1042: Pulse output enabled
M1047: STL monitor enabled S0: Initiates manual operation
S1: Initiates zero return
S2: Initiates auto operation
3. S10 ~ S19 are for zero return and cannot be used as general steps. When S0 ~ S9 are in use, S0 ~ S2 represent
manual operation mode, zero return mode and auto operation mode. Therefore, in the program, you have to write
the circuit of the three steps in advance.
4. When switched to S1 (zero return) mode, any On in S10 ~ S19 will result in no zero return.
5. When switched to S2 (auto operation) mode, any On of the S in D
1
~ D
2
or M1043 = On will result in no auto
operation.
Program Example 2:
1. Robot arm control (by IST instruction):
a) Motion request: Separate the big ball and small ball and move them to different boxes. Configure the control
panel for the control.
b) Motions of the robot arm: descending, clipping ball, ascending, right shifting, releasing ball, ascending, left
shifting.
c) I/O devices:
Y0
Y1
Y2 Y3
Left-limit X1
Upper-limit X4
Lower-limit X5
Right-limit X2
(big)
Right-limit X3
(small)
Big Small
Ball size
sensor X0
2. Operation modes:
Manual operation: Turn On/Off of the load by a single button.
Zero return: Press the zero return button to automatically zero-return the machine.
Auto operation:
a) Single step operation: Press “auto start” button for every one step forward.
b) One cycle operation: Press “auto start” button at the zero point. After a cycle of auto operation, the operation
will stops at the zero point. Press “auto stop” button in the middle of the operation to stop the operation and
press “auto start” to restart the operation. The operation will resume until it meets the zero point.
c) Continuous operation: Press “auto start” button at the zero point to resume the operation. Press “auto stop” to
operate until it meets the zero point.
3. The control panel: