Cutler-Hammer D320 PLC, Руководство пользователя

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Chapter 6: Instructions
91
Instruction
Mnemonic Timer (I) Range
■
Bit
Word
UC
DC Up counter
Down counter
Double words
Example of UC with SV = 3.
Whenever count input condition (U input) turns On, PV
increases by 1. When PV and SV are the same, the output
TC done contact is On. When the reset input condition (R
input) is On, the output contact is Off.
While the count input pulses On, the PV will continue to
count up to a maximum of 65,535. When the reset input is
On, the PV is reset to a value of 0.
Example of DC with SV = 3.
Whenever count input condition (D input) turns On, PV
decreases by 1. When PV is 0, the output TC done contact
is On.
When the reset input condition (R input) is turned On, the
TC done contact is turned Off, and the PV is set to 0.
Description
1. The timer/counter channel can only be used once. It cannot be reused by other timer or
counter instructions (TIM, SST, TOF, RCT, UDC). A maximum of 256 channels (Ch 0 to
Ch 255) can be used.
2. The output done contact is displayed as TC + channel no. in the counter.
3. The elapsed value (PV) of the counter is maintained in case of a power failure and for
retentive purposes.
4. When SV is 0, the output contact (TC) turns On if one pulse of input occurs.
5. SV can be specified from 0 to 65,535.
CAUTION:
Each input condition to the counter should be on its own line of the rung. They
should not share a common contact or be connected in any way.
UC
U CH =
SV =
R
condition
1
condition
3
TC0
(OUT)
Input
(condition 1)
Input
(condition 3)
Present
Value (PV)
Output
(TC)
Set Value
(SV)
1
2
3 4
5
1
0
DC
D CH =
SV =
R
condition
2
condition
3
Input
(condition 2)
Reset
(condition 3)
Present
Value (PV)
Output
(TC)
Set Value
(SV)
2
1
0
0 0
2