Mitsubishi Electric MELSEC FX2N-2LC, User Manual

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FX2N-2LC Temperature Control Block Buffer Memory (BFM) 7
7-8
7.2.9 BFM #12 (CH1) and BFM #21 (CH2) : Set value (SV)
BFM #12 stores the set value of CH1. BFM #21 stores the set value of CH2.
The unit is
°
C, 0.1
°
C,
°
F or 0.1
°
F in accordance with the setting of the input type selection
(BFM #70, BFM #71).
The allowable set range is the selected input range.
When the setting limiter (CH1: BFM #47 and BFM #48, CH2: BFM #66 and BFM #67) is set,
the allowable set range corresponds to the setting limiter.
7.2.10 BFM #13 to BFM #16 (CH1) and BFM #22 to BFM #25 (CH2): Alarm 1/2/3/4 set value
In BFM #13 to BFM #16 and BFM #22 to BFM #25, write the set value of each alarm selected
by the alarm 1/2/3/4 mode setting (BFM #72 to BFM #75).
In the alarm 1/2/3/4 mode setting, four among 14 alarm types can be arbitrarily selected.
BFM #13 to BFM #16 (CH1) and BFM #22 to BFM #25 (CH2) are assigned to the alarm 1
mode, the alarm 2 mode, the alarm 3 mode and the alarm 4 mode respectively in the ascend-
ing order of BFM No. for each channel.
The unit and the allowable range of the set value written to BFM #13 to BFM #16 (CH1) and
BFM #22 to BFM #25 (CH2) vary depending on the selected alarm mode. In accordance with
the setting of the alarm mode setting (BFM #72 to BFM #75), write a proper set value.
7.2.11 BFM #17 (CH1) and BFM #26 (CH2): Heater disconnection alarm set value
In BFM #17, set a value to recognize heater disconnection in CH1. In BFM #26, set a value to
recognize heater disconnection in CH2.
When the heater current measured value of each channel input from CT is smaller than the
value set to BFM #17 (CH1) or BFM #26 (CH2), the heater disconnection alarm (CH1: BFM #1
b9, CH2: BFM #2 b9) turns on.
The display range is from 0.0 to 100.0 A.
When BFM #17/#26 is set to "0.0", the heater disconnection alarm function is disabled.
7.2.12 BFM #18 (CH1) and BFM #27 (CH2) : Auto/manual mode changeover
In BFM #18, change over the mode of CH1. In BFM #27, change over the mode of CH2.
When BFM #18/#27 is set to "K0 (initial value)", the auto mode is selected.
When BFM #18/#27 is set to "K1", the manual mode is selected.
Auto mode:
The measured value (PV) is compared with the temperature set value (SV), PID arithmetic
operation is performed, then the control output (MV) is given.
In the auto mode, the manual output set value (CH1: BFM #19, CH2: BFM #28) is always
equivalent to the control output value.
Manual mode:
The control output (MV) value is fixed to the manual output set value (CH1: BFM #19, CH2:
BFM #28).
The manual output set value can be changed while b13 of the event (CH1: BFM #1, CH2: BFM
#2) is ON even if operation is performed in the manual mode.
The temperature alarm function is effective even in the manual mode.