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7 SSI Input Units
NX-series Position Interface Units User’s Manual (W524)
7-
9 Fu
nct
ion
s
7
7-9
-7 Dat
a Refr
esh S
tatus
1
Double-click the SSI Input Unit in the Multiview Explorer.
The following tab page is displayed.
2
Set the Parity Check parameter.
Data is refreshed in SSI data communications according to the Baud Rate parameter on a cycle that is
longer than the Controller’s I/O refresh cycle. SSI Input Units have the following two methods to check
whether the data was refreshed in the Controller.
• The Data Refresh Status bit is toggled every time SSI data communications are performed. There-
fore, you can use it only with synchronous I/O refreshing, i.e., when SSI communications are syn-
chronized with the I/O refreshing operation of the Controller.
With Free-Run refreshing, SSI communications are sometimes performed more than once during the
Controller’s I/O refresh cycle, and therefore the value of this bit is not dependable.
• Use the Encoder Present Position Refresh Count parameter to determine if the data has been
refreshed when you use Free-Run refreshing.
Parameter name Setting Default Remarks
Parity Check 0: No check
1: Even parity check
2: Odd parity check 0 Changes are applied when the power sup-
ply to the NX Unit is turned ON or the NX
Unit is restarted.
Setting with the Sysmac Studio
7-9-7 Data Refresh Status
Function Description Remarks
Data Refresh Status
bit (SSI Status) This bit is toggled between 0 and 1 every time
the position data is refreshed through SSI data
communications. You can use this bit only when the I/O
refreshing method is set to synchro-
nous I/O refreshing.
Encoder Present
Position Refresh
Count A counter with a range from 0 to 65,535 is
incremented by 1 every time the position data
is refreshed through SSI data communications.
The value returns to 0 after it exceeds 65,535. You can use this variable when the I/O
refreshing method is set to Free-Run
refreshing or synchronous I/O refresh-
ing.