ProSoft Technology MVI69-DFCM - Manual (Page 72)

MVI69-DFCM ♦ CompactLogix or MicroLogix Platform Reference
DF1 Interface Module
Page 72 of 117 ProSoft Technology, Inc.
November 3, 2008
State Description
0 The slave is inactive and not defined in the command list for the master port.
1 The slave is actively being polled or controlled by the master port and
communications is successful.
2 The master port has failed to communicate with the slave device. Communications
with the slave is suspended for a user defined period based on the scanning of the
command list.
3 Communications with the slave has been disabled by the ladder logic. No
communication will occur with the slave until this state is cleared by the ladder logic.
Slaves are defined to the system when the module initializes the master
command list. Each slave defined will be set to a state of one in this initial step. If
the master port fails to communicate with a slave device (retry count expired on a
command), the master will set the state of the slave to a value of 2 in the status
table. This suspends communication with the slave device for a user specified
scan count (Error Delay Count parameter in the configuration file). Each time a
command in the list is scanned that has the address of a suspended slave, the
delay counter value will be decremented. When the value reaches zero, the slave
state will be set to one.
In order to read the slave status table, you should refer to the sample ladder
logic. The ladder logic must send a special block to the module to request the
data. Each port has a specific set of blocks to request the data as follows:
Block ID Description
3002 Request status for slaves 0 to 59 for Port 1
3003 Request status for slaves 60 to 119 for Port 1
3004 Request status for slaves 120 to 179 for Port 1
3005 Request status for slaves 180 to 239 for Port 1
3006 Request status for slaves 240 to 255 for Port 1
3102 Request status for slaves 0 to 59 for Port 2
3103 Request status for slaves 60 to 119 for Port 2
3104 Request status for slaves 120 to 179 for Port 2
3105 Request status for slaves 180 to 239 for Port 2
3106 Request status for slaves 240 to 255 for Port 2
The format of these blocks is as shown below:
Write Block: Request Slave Status
Offset Description Length
0 3002 to 3006 or 3102 to 3106 1
1 to n Spare n
n=60, 120, or 240 depending on what is entered in the Block Transfer Size parameter (refer to the
configuration file).
The module will recognize the request by receiving the special write block code
and respond with a read block with the following format: