West Control Solutions N8080 (for 2xxx) - Manual (Page 13)

3.3.1 Form 1 Message
The master device sends a Form 1 message to ascertain whether a specific
communications address is occupied by an instrument. If there is an instrument at
that address, a reply (with a positive acknowledgement) is received. If there is no
instrument at that address or if there is a communications link failure, no reply is
received. The message from the master device is of the form:
Laa??*
where aa is the address (a two-digit hexadecimal number). The reply from the
addressed instrument is of the form:
Laa?A*
where aa is the same address as in the received message.
3.3.2 Form 2 Message
This message implements a Parameter Read operation. The message from the
master device is of the form:
Laap?*
where aa is the address (a two-digit hexadecimal number)
p is a single-character parameter identifier (see Table 3-1)
The reply, if the Parameter Read operation is successful, is of the form:
LaapnnnnnA*
where aa is the same address as in the received message
p is a single-character parameter identifier (see Table 3-1)
nnnnn is the data (a five-digit hexadecimal number)
If the specified parameter is invalid (e.g. not applicable to the addressed
instrument), the reply is of the form:
Laap00000A*
where aa is the same address as in the received message
p is a single-character parameter identifier (see Table 3-1)
OM091-3 Volume I 3-2
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