Chapter 16 PLC Function ApplicationsC2000 Plus
16-29
Functions of auxiliary relays
Like an output relay Y, an auxiliary relay M has an output coil and contacts a and b, and the number
of times they can be used in a program is unrestricted. Users can use an auxiliary relay M to configure
the control circuit, but cannot use it to directly drive an external load. Auxiliary relays have the following
two types of characteristics:
Ordinary auxiliary relays: Ordinary auxiliary relays will all revert to the Off state if a power outage
occurs while the PLC is running, and will remain in the Off state if power is again turned down.
Special purpose auxiliary relays: Each special purpose auxiliary relay has its own specific use.
Do not use any undefined special purpose auxiliary relays.
Timer functions
Timers take 100 ms as their timing units. When the timing method is an upper time limit, when the
current timer value = set value, power will be sent to the output coil. Timer setting values consist of
decimal K values, and the data register D can also serve as a setting value.
Actual timer setting time = timing units * set value
Counter features
Item 16-bit counter
Type General Type
CT Direction: Score
Setting 0–32,767
Designation of set value Constant K or data register D
Change in current value When the count reaches the set value, there is no longer a count
Output contact When the count reaches the set value, the contact comes On and stays On
Reset
The current value reverts to 0 when an RST command is executed, and the
contact reverts to Off
Contact actuation All are actuated after the end of scanning
Counter functions
When a counter's counting pulse input signal goes Off→On, if the counter's current value is equal to
the set value, the output coil will come On. The setting value will be a decimal K values, and the data
register D can also serve as a setting value.
16-bit counter C0–C79:
16-bit counter setting range: K0–K32,767. (when K0 and K1 are identical, the output contact
will immediately be On during the first count.)
The current counter value will be cleared from an ordinary counter when power is shut off to
the PLC.
If the MOV command or WPLSoft is used to transmit a value greater than the set value to the
C0 current value register, when the next X1 goes from Off→On, the C0 counter contact will
change to On, and the current value will change to the set value.
A counter's setting value may be directly set using a constant K or indirectly set using the
value in register D (not including special data registers D1000–D1199 or D2000–D2799).
If the set value employs a constant K, it may only be a positive number; the set value may be
either a positive or a negative number if the value in data register D is used. The current counter
value will change from 32,767 to -32,768 as the count continues to accumulate.
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