User`s guide

4-2 Using the PCLTA-20 Adapter
Initializing the PCLTA-20 Adapter
Once a PCLTA-20 adapter and PC are powered, the host application must initialize
the PCLTA-20 adapter. If you are using a LonManager or LNS software product, you
may skip to the next section.
When a PCLTA-20 adapter is initially powered, it disables network communications
by entering the
FLUSH
, unconfigured state. The
FLUSH
state prevents the adapter
from responding to network management messages before the host application has
initialized the adapter. The unconfigured state prevents the PCLTA-20 adapter from
responding to application messages before the node has been installed in a network.
The host application will not be able to send or receive application messages until
after it cancels the
FLUSH
state and the PCLTA-20 adapter leaves the unconfigured
state.
To initialize a PCLTA-20 adapter, follow the steps below (these steps are described in
more detail in the
L
ON
W
ORKS
Host Application Programmer's Guide
4
).
Canceling the Flush State
By default, the PCLTA-20 adapter automatically leaves the
FLUSH
state upon reset.
If the Automatic Flush Cancel option has been disabled in the PCLTA-20
Control Panel, the flush cancel must be performed by the host application.
If the host application attempts to send a message while the PCLTA-20 adapter is in
the
FLUSH
state, the adapter will return a failed response for acknowledged messages
and a success response for unacknowledged messages. The message will not be sent
in either case.
If the host application attempts to send a message while the adapter is in the
NORMAL
, unconfigured state, the PCLTA-20 adapter will always return a success
response even though the message was not sent.
To cancel the
FLUSH
state, follow these steps:
1. Reset the PCLTA-20 adapter from the host application by sending the
niRESET
command. If installed correctly, the PCLTA-20 adapter will respond with an
uplink
niRESET
message upon completion of the reset. The first message from
an adapter after the network driver has been opened will also be an uplink
niRESET
command informing the host that the PCLTA-20 adapter has been
released from reset.
2. Cancel the
FLUSH
state in the PCLTA-20 adapter. This is done automatically by
the device driver after an open command or uplink
niRESET
depending on the
setting for
FLUSH
state in the Plug ‘n Play control panel. The
FLUSH
state can be
manually canceled by sending the
niFLUSH_CANCEL
message.
Configuring the PCLTA-20 Adapter with a Network Address
The PCLTA-20 adapter leaves the unconfigured state when it is installed in a
network and is assigned an address in one or two domains on that network. There
are two ways this can happen. If the PCLTA-20 adapter is used as a network
interface for a network tool, then the tool’s application may configure the network