Mitsubishi Electronics MELSEC-F Manuel D’Utilisation

D-8

2 Specifications

2.3 A/D Conversion Time

/FX

3UC

PLC User's Manual - Analog Control Edition

-2AD-BD (2-channel analog Input)

2.3

A/D Conversion Time

This section describes the A/D conversion time.

1. A/D conversion and special data register update timing

A/D conversion is performed at every scan time of the PLC.
During execution of END instruction, the PLC performs A/D conversion, reads out the A/D converted data,
and then writes the data in the special data registers.

2. A/D conversion during PLC STOP

Even if the PLC is stopped, A/D conversion will be performed and the special data registers will be updated.

3. If two analog expansion boards are connected

During execution of the END instruction, data will be read out from all the connected boards (in the order of
1st board

→ 2nd board).

4. A/D conversion speed (data update time)

During execution of END instruction, the A/D converted data of all 2 channels will be read out in 180

μs, and

the data read out will be written to the special data registers.
END instruction execution time will be "180

μs × number of connected analog boards."

Series PLC

Sequence Program

END instruction

A/D conversion
start command

A/D
conversion

1st

180

μs

/2ch

-2AD-BD

180

μs

/2ch

2nd

A/D
conversion

Digital value
reading

A/D conversion
start command