3 Data Exchange with the CPU Unit
3-22
CJ-series PROFIBUS Slave Unit Operation Manual for NJ-series CPU Unit (W510)
Precautions for Correct UsePrecautions for Correct Use
The Slave will exit data exchange mode if the communication watchdog is enabled, and the time
between two PROFIBUS-DP messages received from the master exceeds Twd
+
0
- WDtimebase
ms.
For example, if the Watchdog timeout (T
WD
) has been set to 100 ms and the Watchdog timebase
has been set to 10 ms, two PROFIBUS-DP messages received from the master should not be
more than 90 ms apart.
In this state, the Data exchange active flag (
*_DatXchgActSta) will be off, and all slave output data to
the host CPU will be 0000. The slave needs to receive the correct Set_Prm and Chk_Cfg mes-
sages from the master to re-enter data exchange mode.
The CJ1W-PRT21 unit indicates configuration information and operational behavior settings for slave
output data from the master to the slave (Dm+2, Dm+3 and Dm+4).
1514131211109876543210
*_SlvParamSta
*_SlvWdtFact1
*_SlvWdtFact2
Name of Device Variable for CJ-
series Unit
Type R/W Description Function
*_SlvWdtFact1 USINT R Watchdog Fac-
tor 1
The master's parameterisation telegram con-
tains the value to which the slave's communica-
tion watchdog timer will be set. The actual
watchdog control time is set with *_WDfact1,
*_WDfact2, *_WD timebase.
The WD timebase can be either 10 ms (default)
or 1 ms (optional). This selection is made by the
PROFIBUS master and indicated in
*_WdtTmBaseSta
The actual watchdog control time can have any
value from 2 ms (2*1*1) to 650250 ms
(255*255*10).
A value of 00 means that the slave has not
been parameterized.
The values are provided by the PROFIBUS
master's Set_Prm telegram, and indicated in
*_SlavOutStartAdrSta after both the Set_Prm
and Chk_Cfg telegrams have been accepted.
*_SlvWdtFact2 USINT R Watchdog Fac-
tor 2
3-7-2 Slave Output Data (*_SlvOutSta)
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*_SlvOutSta
*_SlvOutAreaCode
*_SlvOutHoldBusErr
*_SlvOutIntelMd
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