Mitsubishi Electric MELSEC-Q Series User Manual page 167

10 DEVICES
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(3) Output method
(a) There are 2 types of output: "refresh outputs" and "direct access outputs".
1) Refresh outputs are ON/OFF data which is output to the output module
using the refresh mode.
Output refresh area
0
These outputs are indicated as "Y " in the sequence program.
For example, a "10" input becomes "Y10".
2) Direct access outputs are ON/OFF data which is output to the output
module using the direct mode.
Output refresh area
0
These outputs are indicated as "DY " in the sequence program.
For example, a "10" input becomes "DY10".
(b) Differences between refresh outputs and direct access outputs
With direct access outputs, the output module is directly accessed by
executing an instruction, and the processing speed is therefore slower
than that for refresh outputs.
A refresh output takes longer to process instructions than a direct
access output.
Moreover, direct access outputs can only be used for outputs used with
the output module and intelligent function module which are installed at
base unit and extension base unit.
The refresh and direct output differences are shown in Table 10.3 below.
Table 10.3 Differences Between Refresh Outputs & Direct Access Outputs
Item
Output module installed at main/extension
base unit
Outputs of intelligent function module
installed at base/extension base unit
Outputs used at MELSECNET/H network
system or CC-Link system
REMARK
1: See Section 4.7.1 for details regarding the refresh mode.
1
CPU module
ON/OFF data output
Y10
CPU module
DY10
ON/OFF data output
Refresh Input
2
Direct Access Outputs
Usable
Usable Unusable
MELSEC-Q
Output module
Output module
Usable
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