IAI America ERC3 - Manual (Page 428)

Chapter 10
Appendix
10.5
Example of Basic Positioning Sequence (PIO Patterns 0 to 3 in PIO Converter)
418
[11] Commanded Position No. Output Ready Circuit
The ready circuit is designed to hold start command and output commanded position No. in the
binary code.
Interlock is taken so that position No. command may not be specified incorrectly.
135
AUX18
142
AUX19
149
AUX20
a136 b146 b153
a156
Position 1 Set
b139 b143 b154
a159
Position 2 Set
b140 b147 a150
a157 a160
Position 3 Set
AUX9
Auxiliary
Position 1
Positioning
Start
AUX12
Auxiliary
Position 2
Positioning
Start
AUX15
Auxiliary
Position 3
Positioning
Start
AUX19
Position 2
Set
AUX20
Position 3
Set
AUX18
Position 2
Set
AUX12
Auxiliary
Position 2
Positioning
Start
AUX9
Auxiliary
Position 1
Positioning
Start
AUX15
Auxiliary
Position 3
Positioning
Start
AUX18
Position 1
Set
AUX20
Position 3
Set
AUX19
Position 2
Set
AUX15
Auxiliary
position 3
positioning
start
AUX9
Auxiliary
position 1
positioning
start
AUX12
Auxiliary
position 2
positioning
start
AUX18
Position 1
set
AUX19
Position 2
Set
AUX20
Position 3
Set
Position No.1, 2,
or 3 set relay
Position No.1, 2,
or 3 start command
To commanded position No.
output circuit
To commanded position No.
output circuit
To commanded position No.
output circuit
• Once a moving command to a position is issued, any of circuits A, B and C is turned ON to
remember it unless a moving command to another position is issued. The operation circuit is
cancelled by a stop command such as an emergency stop command. However, the circuit
remembers the positions to which the actuator moved and the positions at which the actuator
stopped until the cancellation. Such sequence design is also intended to cope with errors
occurred and helpful to find the causes of the errors from circuit status, stop position
inconsistency and other conditions.
• Taking interlock in both commands and results is usual means in circuit design to prevent results
from being ON simultaneously. For example, if both SOLs in a solenoid valve of double SOL
type are turned ON simultaneously, the coils are burned instantly. In another case, PLC
executes a program in descending order but operations are not always done in the order. If you
create a sequence program taking operation order into account, circuit change and/or addition
due to debugging and specification change may cause the operation order to be modified
without intention. Take interlock securely.