Operation
40
Auto Reset Timing Diagrams (continued)
Fig 5.6.4 Auto Reset - Three Wire - Control Supply Loss
The timing diagrams show the auto reset with Three wire / Modbus control
The fault shown is a 3-phase supply loss
and
Control supply loss
The 3-Phase power and control supply are re-established (after the 2nd attempt) before the Reset Attempts counter is depleted
This assumes the momentary stop signal is not activated, if it is the Auto Reset terminates
Once power has been re-established there are no further outages and the counters are reset after the trip free time.
3-Phase Supply voltage
Control Supply
Start Signal
Stop Signal
Reset Input
(1)
Fault Relay
Restart Pending Relay
Imotor
Internal Reset
Reset Attempts PNU = 4
t0
t1
t2
t3
t4
t5
t6
t7
t8
t9
t10
Sequence of events
User Parameters (R/W)
Monitor Parameters (R/O)
t0 3 phase supply applied
PNU
Range
Default
PNU
Range
t1 Start signal applied, motor starts
Auto Reset
Off / On
Off
A
uto
R
eset Pending
0-1
t2 Motor reaches full voltage
Reset Delay
0-7200s
0s
A
uto
R
eset Exceeded
0-1
t3 3 phase supply removed
Reset Attempts
0-10
0
A
uto
R
eset Delay Remaining
0-7200s
t5 Reset delay = 0 Restart Attempts = 3
Reset Trips
All resettable trips -
A
uto
R
eset Attempts Remaining
0-10
t7 Reset delay = 0 Restart Attempts = 2
Trip Free Time
0-7200s
600s
A
uto
R
eset Trip Free Time Remaining0-7200s
t8 3-Phase re-established
Start signal must still be applied
Notes
If it has been removed Auto Reset feature re-initialises
The controller is powered down between t3 and t8 ( yellow shaded region)
Rest Signal must be low
During this time controller is unable to make the calculations in real time
If the trip is reset the Auto Reset feature re-initialises
To overcome this the calculations are made retrospectively at time t8
t9 Reset delay = 0 Restart Attempts = 1
Start signal state saved at power down and loaded at power up.
This means it will start without a start signal being present
t10 Trip Free Delay = 0 Restart Attempts = 4
If the time to re-establish the power exceeds (Reset Delay x Reset Attempts) to Auto Reset terminates
(1) Seperate reset signal not avialble on all products
Reset Attempts = 4
Reset Delay
Reset Delay
Reset Delay
Trip Free Time
Reset Attempts = 4
Reset Attempts = 3
Reset Attempts = 2
Reset Attempts = 1
