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 Use
Precautions 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).
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
*_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)
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
*_SlvOutSta
*_SlvOutAreaCode
*_SlvOutHoldBusErr
*_SlvOutIntelMd
