Mitsubishi FX3U-4AD User Manual page 111

FX /FX /FX PLC User's Manual - Analog Control Edition
3G 3U 3UC
FX -4AD/FX -4AD (4-channel Analog Input)
3U 3UC
5.4.9 BFM #26: Upper/lower limit error status
If channel data (BFM #10 to #13) is out of the range set by the lower limit error data (BFM #71 to #74) and the
upper limit error data (BFM #81 to #84), the following operation will be performed:
• If "channel data < lower limit error set value":
The lower limit error bit will turn on.
• If "channel data > upper limit error set value":
The upper limit error bit will turn on.
1. BFM #26 bit assignment
The upper and lower limit error values of each channel are assigned as shown in the following table:
Bit No. Channel number
b0
b1
b2
b3
b4
b5
b6
b7
b8 to b15 Not used.
2. Cautions regarding use of upper/lower limit error status data
• To use the upper/lower limit error status data, be sure to turn on the upper/lower limit detection function (b1
of BFM #22).
• Perform one of the following operations to turn off the previously turned on bit:
- Turn the power off and on.
- Turn on b0 or b1 of BFM #99 to reset the upper/lower limit error status.
- Write "H0000" in BFM #26 as the upper/lower limit error status data.
• Even if an error is detected, channel data (BFM #10 to #13) will be continuously updated.
3. Upper/lower limit error status data automatic transfer function (b5 of BFM #22)
If the upper/lower limit error status data automatic transfer-to data register is specified in BFM #126, the data
in BFM #26 can be transferred to the specified data register.
When the upper/lower error is detected, data will be automatically transferred from the 4AD to the PLC. For
this reason, the PLC does not need the program for reading data, and the scanning time of the PLC can be
shortened.
Convenient function
setting
ON = Valid
BFM #22 b1:ON
BFM #22 b5:ON
→ For a detailed description of upper/lower limit error status data resetting,
Lower limit error value
ch1
Upper limit error value
Lower limit error value
ch2
Upper limit error value
Lower limit error value
ch3
Upper limit error value
Lower limit error value
ch4
Upper limit error value
Transfer-from buffer memory
BFM #26
Numeric data type: Hexadecimal (H)
Description
Automatic data transfer function
Transfer-to data register specification
→
5 Buffer Memory (BFM)
5.4 Buffer Memory Details
Initial value: H0000
refer to Subsection 5.4.18.
: Represents a numeric value.
(BFM #126: K )
D
B-35
A
B
C
D
E
F
G
H
I
J