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CHAPTER 4 FUNCTIONS
4
4.28 Heater Disconnection Detection Function
4.28 Heater Disconnection Detection Function
When transistor output is on, whether a heater is disconnected or not can be checked based on a reference heater
current value (load current value detected by a current sensor (CT)) using this function. A reference heater current
value and heater disconnection alert current value are compared. When the reference heater current value becomes
lower than the heater disconnection alert current value, the heater is regarded as disconnected.
Heater disconnection is detected every 500ms. When transistor output is on for 500ms or less, heater disconnection is
not detected. (CH Heater disconnection detection (b12 of Un\G5 to Un\G8) remains 0 (OFF).) ( Page 87,
Section 3.4.2 (3))
The following is the timing output as an alert.
• 500ms × Setting value in Heater disconnection/output off-time current error detection delay count (Un\G166)
If a heater is disconnected longer than the time described above, Alarm code (04A
H
) is stored in Write data error
code (Un\G0). ( Page 370, Section 8.7)
(1) Modules where this function can be used
• Q64TCTTBWN
• Q64TCRTBWN
(2) Setting method
Follow the instructions below.
1. Set the current sensor (CT) to be used in CT CT selection (Un\G272 to Un\G279). ( Page 140,
Section 3.4.2 (55))
2. When using a current sensor (CT) other than CTL-12-S36-8 and CTL-6-P(-H) manufactured by
U.R.D.Co., LTD., set CT CT ratio setting (Un\G288 to Un\G295). ( Page 141, Section 3.4.2 (57))
3. Set the CT input assigned to each channel in CT CT input channel assignment setting (Un\G264
to Un\G271). ( Page 139, Section 3.4.2 (54))
4. Monitor CT Heater current process value (Un\G256 to Un\G263) and check the current value of
when the heater is on. ( Page 138, Section 3.4.2 (53))
5. Set the value monitored in CT Heater current process value (Un\G256 to Un\G263) in CT
Reference heater current value (Un\G280 to Un\G287). ( Page 141, Section 3.4.2 (56))
6. Set the judgment value to perform the heater disconnection detection and output off-time current
error detection
*1
at the rate of the reference heater current value (%) in CH Heater disconnection
alert setting (Un\G58, Un\G90, Un\G122, Un\G154). ( Page 123, Section 3.4.2 (32))
7. Set how many times heater disconnection is detected successively to regard the heater as
disconnected in Heater disconnection/output off-time current error detection delay count
(Un\G166). ( Page 130, Section 3.4.2 (40))
*1 For details on the output off-time current error detection function, refer to Page 269, Section 4.29.
Common