ProSoft Technology MVI56-LTQ - Manual (Page 62)

Reference MVI56-LTQ ♦ ControlLogix Platform
User Manual Limitorque Valve Actuator Master Communication Module
Page 62 of 98 ProSoft Technology, Inc.
August 30, 2010
The LTQ Module returns Done Bit Data to the ladder logic. A single bit is
returned per slave address, allowing ladder logic to be used to clear the
Command Enable bits. The following important points should be noted about the
Command Done bits:
1 There is only one bit returned per slave address, not one bit per command
per slave. The implication of this is that one Done Bit must be used to clear
all possible Enable bits for one slave address.
2 The Done Bit is a positive indication that the module executed the command.
It is NOT an indication of the command’s success. A Done Bit is returned to
the ladder logic whenever the command was completed without error or not.
This allows all commands to be unlatched. To determine if there is a
communication problem with a slave, verify the Channel A/B communication
status bits in the valve data Status field.
3 The Done Bit data registers in the module are cleared and then updated prior
to each backplane transfer sequence. This is done to ensure that the ladder
logic receives the quickest possible acknowledgment of a command’s
execution.
The structure of the Done Bit Data in the input image from the module is as
follows:
Word Description
202 Cmd Done - Slaves 1 to 16
203 Cmd Done - Slaves 17 to 32
204 Cmd Done - Slaves 33 to 48
205 Cmd Done - Slaves 49 to 64
206 Cmd Done - Slaves 65 to 80
207 Cmd Done - Slaves 81 to 96
208 Cmd Done - Slaves 97 to 112
209 Cmd Done - Slaves 113 to 128
210 Cmd Done - Slaves 129 to 144
211 Cmd Done - Slaves 145 to 150
The following tables can be used to determine the slave associated with each bit
in the array. These tables can also be used with the digital control words
discussed in the following section. The following table lists the relationship
between the word/bit combination and the slave address on the Limitorque valve
network: