Toshiba ICC Multiprotocol Ethernet Interface ASD-G9ETH User Manual download pdf (Page 79)

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Figure 80: Reading Via Multiple MSG Instructions

13.2.8 ControlLogix Example: Reading and Writing

Often times, applications may need to both read data from and write data to the

drive. At a minimum, this will require two MSG instructions and two message

controller tags. Figure 81 shows an example of two MSG instructions, one for

reading and one for writing. The only item of note that differentiates this

example from the multiple-read example in section 13.2.7 is the addition of the

en_wr XIC element. The reason for the addition of this element is that while

reading from a remote device is often continuously performed (monitoring),

data is typically written to the remote device only when necessary (i.e. when the

value to write has changed). This conserves both network bandwidth and

potentially EEPROM lifespans on the target device. The en_wr element in this

example, therefore, would typically be replaced in an actual application program

by user-provided logic which controls the conditions under which a write

operation would be performed.

Figure 82 shows the configuration details of the example wr_connection MSG

instruction. Note that the chosen “Message Type” is “CIP Data Table Write”,

and that this instruction will only be writing to one drive register: namely, the

frequency command (Destination Element is wr_reg_1008). The Source

Element in this case is the 8

element (starting from index 0) of an INT array

tag named “wr_data_array”.

1 2 ... 74 75 76 77 78 79 80 81 82 83 84 ... 99 100

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Toshiba ICC Multiprotocol Ethernet Interface ASD-G9ETH User Manual Page 79