Mitsubishi Electronics MELSEC-F Manuel D’Utilisation

G-8

2 Specifications

2.3 D/A Conversion Time

/FX

3UC

PLC User's Manual - Analog Control Edition

-1DA-BD (1-channel analog Output)

2.3

D/A Conversion Time

This section describes the D/A conversion time.

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

D/A conversion is performed at every scan time of the PLC.
During execution of the END instruction, the PLC writes the output setting data of the special data registers,
performs D/A conversion of the data, and updates the analog output data.

2. D/A conversion during PLC stop

If the output holding function cancellation setting is disabled by the special device, the offset value will be
output.
If the output holding function cancellation setting is enabled, the output at switching from RUN to STOP will be
latched.
Just after power-on, however, the offset value will be output until operation begins.

3. If two analog expansion boards are connected

During execution of the END instruction, data in all the connected boards will be subject to D/A conversion
and then output (in the order of 1st board

→ 2nd board).

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

During execution of END instruction, the output setting digital data will be subject to D/A conversion which
takes 60

μs, after which the analog data will be output.

END instruction execution time will be "60

μs × number of connected board."

Series PLC

Sequence Program

END instruction

1st

-1DA-BD

/1ch

μs

/1ch

μs

2nd

D/A conversion
start command

D/A
conversion

Digital value
writing

D/A conversion
start command