Omron Sysmac CJ Series, Operation Manual

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56
Setting the Set Point Section 3-7
Starting DM Area Word The starting DM Area word (m) for a Special I/O Unit is:
m = 20000 + (100
×
unit number)
3-7 Setting the Set Point
3-7-1 Setting the SP
Set the set point (SP) in the corresponding word of the Operation Data in the
CIO words allocated to the Unit. (See the following table.)
When setting the set point, use the data format set with pin 3 of the DIP switch
on the front of the Unit. The temperature units are set on pin 2 of the DIP
switch and the default setting is 0 s or 0.0 s.
Example To change the loop 1 set point from 0 to 200
°
C, write a value of 0200 to CIO
word n if the Unit’s data format is set to BCD or write a value of 00C8 to CIO
word n if the Unit’s data format is set to binary.
Note Changing the set point is not enough to start temperature control, it is also
necessary for the Stop Bit for that loop to be OFF. See
3-12 Starting and Stop-
ping Temperature Control for details.
Starting CIO Area Word The starting CIO Area word (n) for a Special I/O Unit is:
n = 2000 + (10
×
unit number)
3-8 Using ON/OFF Control
With ON/OFF control, you set a set point in advance. During reverse opera-
tion, the Temperature Controller will turn OFF the control output when the set
point is reached. When the control output goes OFF, the system temperature
will begin to drop and the control output will be turned ON again when the sys-
tem temperature falls below the set point. This ON/OFF operation is repeated
around the set point.
The control sensitivity setting determines how far the system temperature has
to fall below the set point before the control output is turned ON again. Also,
the control operation setting determines whether the Unit operates with for-
ward operation (cooling) or reverse operation (heating). With forward opera-
tion, the manipulated variable increases as the PV increases; with reverse
operation, the manipulated variable decreases as the PV increases.
3-8-1 ON/OFF Control Operation
Pin 6 of the DIP switch on the front of the Unit selects whether the Tempera-
ture Control Unit uses ON/OFF control or PID control with 2 degrees of free-
dom. The Unit will use PID control if pin 6 is OFF; it will use ON/OFF control if
pin 6 is ON. The factory setting is PID control.
Control Sensitivity In ON/OFF control, the ON and OFF switching creates a stable hysteresis
loop. The width of the hysteresis loop is called the control sensitivity.
CIO word Setting Setting ranges
BCD Binary
CIO (n) Loop 1 SP (set point) The setting ranges depend on the input type
set with the Input Type Switch on the front of
the Unit. Refer to
2-3-5 Setting the Input Type .
CIO (n+1) Loop 2 SP (set point)
CIO (n+10) Loop 3 SP (set point)
CIO (n+11) Loop 4 SP (set point)