PSx3xxDN Instruction Manual
19
Deactivating timeout monitoring for the UCMM connection, for instance, requires the
following explicit message:
Message ID = 0
Destination MAC ID = slave address
Service code = 0x10
Class ID = 5
Instance ID = 5
Attribute ID = 9 (expected packet rate)
Value = 0x0000 (16 bit)
c) Explicit connection
Explicit messages can be used to read and write the attributes from a).
Identifier:
Message ID = 0
Source MAC ID = address of the master
Message group = 3
Content:
Destination MAC ID = slave address
Service code = 0x10 (write); 0x0E (read)
Class ID = 100
Instance ID = 1
Attribute ID according to list a)
Value (if written)
d) I/O connections
The PSx3xxDN supports the following types of I/O messages:
Poll (class ID 5, instance 2)
Bit strobe (class ID 5, instance 3)
Change-of-state/cyclic (class ID 5, instance 4), with or without master
acknowledge
Setting up an I/O connection first requires the use of an explicit connection to allocate
the desired I/O connection; the corresponding identifiers are then reserved and the
connection is set to "configuring" status. The next step is to set the expected packet
rate, after which point the I/O connection will be in place.
The expected packet rate is always attribute 9 (for a given instance in class 5).
WARNING:
Activating the change-of-state/cyclic connection may cause the CAN bus
to be flooded with messages as soon as the EPR has been set; to prevent this from
occurring, the inhibit time (class ID 5, instance 4, attribute 17), which indicates the
minimum amount of time that must elapse before a change-of-state event actually
triggers an I/O message, should be set prior to establishing this type of connection.
Only then should the EPR be set.
e) Mapping I/O assemblies
The following 4 assemblies are permanently stored in the PSx3xxDN:
Assembly object (class ID 4),
instance 100
, attribute 3: