Watlow Series 942 Data Communications - Manual (Page 10)

10 WATLOW Series 942 How to Use Data Communications
Syntax
Message Syntax
Messages from your computer to the Series 942 must take this general form.
All commands do not require the full number of data fields.
Command Data.1 Data.2 Data.3... Data.N
"Command" is a character set to which the Series 942 will respond. The
brackets "< >" enclose a non-literal description. "Space" is simply a delimiter,
an ASCII space character (Hex 20). "Data Fields" are parameters and values
specific to a command; the number of possible data fields depends on the
particular command you use. Data 1 is here abbreviated, "Data.1", Data 2 is
"Data.2" and so on.
In the syntax explanations ahead, we'll show you the specific arguments for
each command. It will speed the process, if you remember this general syntax.
Data Rules
Data fields are parameters and values specific to particular commands. These
rules govern their use. Specific data for each command is listed later in this
chapter.
• Data will be ASCII 0 through 9, unless otherwise noted.
• Data can go up to seven total characters, including a minus sign. A + or -
sign, if used, must be first, and it must have a decimal point if applicable.
• Data can use leading zeros. (Up to 7 digits.)
• Data does use decimal points.
• Data.1 portion of message can be up to four total characters.
Series 945 General Message Syntax
As soon as you link the devices, you'll be able to talk to the Series 942 using
ASCII characters.
The Series 942 will respond to any operating or set up parameter, plus some
others. The control will respond to either upper or lower case ASCII characters
from your computer.
Both protocol/interface combinations will respond to the general syntax,
providing the commands or queries are correctly transmitted. However, the
ANSI X3.28 Protocol requires beginning and ending characters, and the
XON/XOFF Protocol requires ending characters. We'll look at those shortly.