Operating Instructions
IS1 PROFIBUS 3.00 E
- Technical alterations reserved -
78
PROFIBUS DP interface for IS1+
Behavior of the output signals in case of errors
Communication error between the master and IS1+ field station:
The cyclic data traffic between the class 1 master and the IS1 is checked in the IS1 using response monitoring.
Response monitoring in the CPU makes sure that if the master suffers a failure or there is some other
communication loss to the master after expiry of the time (T
WD
), the outputs adopt the safe state.
The T
WD
time can be parameterized in the class 1 master within the range 10 ms to 650 seconds and is
transferred by means of the "SET_PARAMETER" DP service from the master to the CPU.
After expiry of T
WD
,
the cyclic updating of the output modules is stopped by the CPU of the IS1+ field station.
The response monitoring of the slaves can also be deactivated by the master. In this case, the slave cannot
recognize a loss of communication to the master. The output signals of the slaves are frozen if updating from
the master cannot be performed.
Communication error between the CPU and output module:
There are Watchdog circuits on the output modules that monitor the data transmission between the CPU and
the output modules. If an output module does not receive any valid data for more than T
Mod
, the subassembly
adopts the safety position.
T
MOD
(timeout for output modules) can be parameterized in the DP master within the range 100 ms to 25.5
sec. (default value: 100 ms).
Consequently, the safety position of the output modules follows at a delay of T
S
after failure of the
communication to the master where:
The safety position of the output signals can be parameterized separately for every module (see 3.2.2 IO-
Module parameters).
PROFIBUS Failsafe Mode Support:
Behavior of different IS1 CPUs in the PROFIBUS DP clear mode.
IS1
GSE
Failsafe
Mode
GSE:
Fail_safe =
Cyclic Data from DP Master
on DP Bus in DP Clear Mode
Global
Control
Clear
Safety position of
Output Signals in IS1
parameterisable
V2.xx
V3.xx
Without
0
Length of Output Data unchanged.
All Output Signals = 0
Yes
9440 CPM: Yes
9442 CPU: No
Output Signals = 0
V4.xx
V5.xx
With
1
Length of Output Data Telegram = 0
Yes
9442 CPU: Yes
Using the 9442 CPU with GSE V2.xx or V3.XX all output signals are set to the value ´ 0 ´ in the DP
clear mode regardless of the parameterized safe positions in the IS1 parameters.
Using the 9440 CPM or 9442 CPU with GSE V4.xx or V5.xx, the projected security positions of the
output signals are processed correctly as parameterized in the IS1 parameters.
T
S
= T
WD
+ T
Mod
