Rice Lake Allen-Bradley Remote I/O - Manual (Page 17)

Block Transfer Commands 13
4.1 Block Write Command Format
The format for sending a block write command includes a minimum of two words. The first word always
contains the command to be executed by the indicator. The second word contains one or more parameters
necessary to execute the command, such as a scale number or setpoint number. If a command requires additional
values, this data follows, generally as one or more 4-byte, single-precision floating-point numbers. Below is a
general outline and example for setting up a data file for a block write command.
Table 4-2. Block Write Command Format Example
Word Description Sample Data Description
0 Command number (hex) 0x010C Set Tare command
1 Parameter data (hex) 0x0000 Current scale
2 Value, MSW 125.0 Tare value
3 Value, LSW
4.2 Block Read Command Format
Block read commands have a similar format. The first word echoes the command number. If the command fails
or is not recognized, the negative of the command number is returned to signal the error. The second word
contains a status of the indicator for the scale selected, or a batch status for setpoint commands. Data being
returned to the PLC follows, as required by the command, generally as one or more 4-byte, single-precision
floating-point numbers. Below is a general outline and example for setting up a data file for a block read
command.
Table 4-3. Block Read Command Format Example
Word Description Sample Data Description
0 Command number 0x0151 Read Multiple Setpoints command
1 Status data 0x0B02 Batch status
2 First value, MSW 150.0 Setpoint 1 value
3 First value, LSW
4 Second value, MSW 225.0 Setpoint 2 value
5 Second value, LSW