B&B Electronics 232OPSDA manual Commands

Chapter 3: Commands

Only three commands are required to operate the 232OPSDA: the read A/D command, read digital I/O command, and the set digital output command. The command string consists of four bytes. The read A/D and digital I/O commands require an additional data byte. See Table 3.1.

Table 3.1: 232OPSDA Commands

Function	Command	Response
Read A/D	!0RA{#}	{ch#msb}{ch#lsb}{ch(#-1)msb}…
Channels		{ch0msb}{ch0lsb}
Read	!0RD	{I/O states}
Digital I/O
Set Digital	!0SO{#}	no response
Output

NOTE: Each {…} represents one byte.

In addition to the commands mentioned above, an extended set of commands are provided that support bit-error identification. These commands use the “#” character in place of the “!” character, and the compliment of the data byte must be sent after the data byte. The extended commands are shown in table 3.2.

Table 3.1: 232OPSDA Commands

Function	Command	Response
Read A/D	#0RA{#}~{#}	{ch#msb}~{ch#msb}{ch#lsb}{ch#lsb}
Channels		{ch(#-1)msb}~{ch(#-1)msb}….{ch0msb}
		~{ch0msb}{ch0lsb}~{ch0lsb}
Read	#0RD	{I/O states}~{I/O states}
Digital I/O
Set Digital	#0SO{#}~{#}	no response
Output

NOTE: ~{…} represents the complement of one byte.

Before going into the specifics of each command, it is important to understand that a byte has a value from 0 to 255 and can be represented in decimal (0 to 255), hexadecimal (00 to FF), or by an ASCII character. The commands in Table 3.1 are shown in ASCII, for example: “!0RD”. The decimal and hexadecimal equivalents of some ASCII characters are shown in Table 3.2. Notice that the ASCII representation of the character “0” does not have a value of 0. Refer to Appendix A for more ASCII, decimal, and hexadecimal equivalents.

Documentation Number 232OPSDA1397 Manual 11

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