Mitsubishi Electric FX3G User Manual page 110

FX /FX /FX /FX /FX
3S 3G 3GC 3U
FX -4AD/FX -4AD (4-channel Analog Input)
3U 3UC
2. Outline of buffer memory
The analog signals input into the 4AD will be converted into digital values and then stored in the 4AD buffer
memory.
To switch the input mode between voltage input and current input, or to adjust the offset or gain, numeric data
will be sent from the main unit and written/set in the 4AD buffer memory.
To read/write data from/to the 4AD buffer memory, the buffer memory can be directly specified using the
FROM/TO instruction or an applied instruction. Using this function, sequence programs can be easily created.
Main unit
Sequence
program
*1. Since buffer memory direct specification (U\G) can directly specify the buffer memory in the source or
destination area of an applied instruction, programs can be created efficiently. (This function is supported
only in FX
3U
B-20
PLC User's Manual - Analog Control Edition
3UC
• BFM direct
specification *1
• TO instruction
• BFM direct
*1
specification
• FROM
instruction
/FX PLCs.)
3UC
→ For a detailed description of buffer memory reading/writing, refer to Section 5.2.
→ For a detailed description of the buffer memory, refer to Section 5.4.
5.1 Assignment of Unit Numbers and Outline of Buffer Memory
• BFM direct
4AD
specification
• TO instruction
• BFM direct
specification
• FROM instruction
Buffer
memory
Digital
value
A/D
conversion
Analog data
Flowmeter, pressure sensor, etc.
5 Buffer Memory (BFM)
4AD
*1
Buffer
memory
*1
Digital
value
A/D
conversion
Analog data