DN120 DeviceNet Gateway User’s Manual
Microscan Systems, Inc.
26
Configure DeviceNet Master Scan List
You must calculate the number of input and output bytes required by your DN120 configuration
before you can add the gateway to the DeviceNet master scanlist. You need to configure the
DeviceNet master to send the specific number of output bytes in its Poll Command Message, and
receive the specific number of input bytes in the gateway’s Poll Response Message. Once the
input and output bytes are mapped in the DeviceNet master, the user application program will be
able to read and write data values to the input and output bytes.
Poll Consume Size
The
Poll Consume Size
is the size (in bytes) of the Poll Command Message data field that is sent
by the DeviceNet master to the DN120.
Poll Command data:
[Status Clear byte][Transmit Sequence Number byte][Short_String length byte][TX data bytes (0-64)]
The first 3 bytes are present if enabled. The following equation is used to calculate the DN120
Poll Consume Size
. Only include the overhead bytes that are enabled.
Status Clear byte
1
Transmit Sequence Number byte
1
Short_String length byte
1
+
Maximum Transmit Size
____
Poll Consume Size
____
Poll Produce Size
The
Poll Produce Size
is the size (in bytes) of the Poll Response Message data field that is sent
from the DN120 to the DeviceNet master.
Poll Response data:
[Status byte][Receive Sequence Number byte][Short_String length byte][RX data bytes (0-64)]
The first 3 bytes are present if enabled. The following equation is used to calculate the DN120
Poll Produce Size
. Only include the overhead bytes that are enabled.
Status byte
1
Receive Sequence Number byte
1
Short_String length byte
1
+
Maximum Receive Size
____
Poll Produce Size
____
