Watlow Series 1500 - Manual (Page 62)

Technical Reference
Command Rules
The following listing shows the command and the typical Series 1500's response string. The labels beneath
each parameter in
a
command or response string are here for your information only: they will not appear on
your computer screen.
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A command word with a question mark is a direct request for a response, a query.
The__'s in the pages that follow are the number of character positions in a parameter available for entry
or response.
Each parameter in a string must have at least one digit or an asterisk entered.
To avoid making any entry for a given parameter, enter an asterisk in the string.
Each parameter in a string must be separated by at least one space.
Decimal points shown in the typical string must be understood; they are not transmitted or received.
The Series 1500 responds to and sends the minus sign, indicating a negative value.
Whenever you send an STP command (to enter step parameters) the Series 1500 is automatically halted.
The correct protocol must be applied to each command string for the communications to function.
Parameter limits are listed in the Guarded Access and General Parameter Charts located in this section.
An operator at the Series 1500 front panel and an operator at a computer remotely-linked to the same
Series 1500 both have equal access to the controller. Priority is on a first in, first out basis.
Communications are not affected in any way by the keyboard lockout status.
RS-422, STX-ETX.
In RS-423 a *CR’ (carriage return) is the required line terminator.
With the RS-422 interface, the Series 1500
sends an “ACK” or “NAK”
after each command. For a
“NAK,” you may use “ERR? " to determine the cause of the error.
With the RS-423 interface there is no automatic indication of a successful command. You may
query
“ERR? " after
each command to determine if the Series accepted it.
62
WATLOW Series 1500 User’s Manual Data Communications, Commands and Syntax, Chapter
4