Mitsubishi Electronics Q64TCRTN Network Card User Manual


 
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The standard setting value for CH Heater disconnection alert setting (Un\G58, Un\G90, Un\G122, Un\G154) is 80%.
However, the current value may significantly change depending on the characteristics of a heater or how the heater is
used. Check that there is no problem in the actual system.
A write data error (error code: 4
H
) occurs if the current value to be used as a judgment value to detect heater
disconnection (reference heater current value × CH Heater disconnection alert setting (%)) is within 0.1A under one of
the following situations:
•CT CT selection (Un\G272 to Un\G279) is set to When CTL-12-S36-8 (0.0A to 100.0A) is used (0).
•CT CT selection (Un\G272 to Un\G279) is set to When CT ratio setting is used (0.0A to 100.0A) (2).
In addition, when CTL-6-P(-H) used (0.00A to 20.00A) (1) has been set and the current value to be used as a judgment
value to detect heater disconnection (reference heater current value × CH Heater disconnection alert setting (%)) is
within 0.01A, Write data error (error code: 4
H
) occurs.
(3) Heater disconnection compensation function
When heater voltage is dropped, heater current is reduced. The Q64TCTTBWN and Q64TCRTBWN detect
heater disconnection by measuring heater current; therefore, an accidental alert may occur due to a voltage
change caused by a reduced heater voltage.
The heater disconnection compensation function offsets the amount of heater current reduced (heater
disconnection compensation), preventing disconnection from being detected.
(a) Calculation formula for heater disconnection compensation
Calculate (CH Heater current) - (reference heater current value). The largest positive value is the correction
value. When there is no positive value, the value with the smallest gap is the correction value. The heater
current for each channel is corrected using a correction value. When the corrected value is larger than the
heater disconnection alert setting value, heater disconnection is found.
Ex.
When CH Heater disconnection alert setting (Un\G58, Un\G90, Un\G122, Un\G154) is 80% and the
differences between CH Heater current and the reference heater current value are the following values:
CH1: -2%
CH2: 5%
CH3: -1%
CH4: -17%
The following table lists the result.
In the table above, the correction value is 5%. Heater disconnection is detected based on the differences
of -7% for CH1, 0% for CH2, -6% for CH3, and -22% for CH4. When Heater disconnection alert setting is
set to 80%, disconnection is detected only for CH4.
Channel
CH Heater
disconnection alert
setting (Un\G58, Un\G90,
Un\G122, Un\G154)
Difference between
CH Heater current
and reference heater
current value
Correction
value
Difference between
CH Heater current and
reference heater current
value after correction
Disconnection
detected
CH1
80 (
%)
-2
%
5%
-7% (= -2% - 5%)
Not detected
CH2
5
% 0% (= 5% - 5%)
Not detected
CH3
-1
% -6% (= -1% - 5%)
Not detected
CH4
-17
% -22% (= -17% - 5%)
Detected