Siemens SIMATIC TIWAY 1 User Manual page 185

USING THE NON-INTELLIGENT TERMINAL PROTOCOL
A.2.2 Response Timeouts
The adapter will respond with ERROR RESPONSE 0001 if the network
response has not returned within the Host Command Timeout period set on
Dipswitch 1. The secondary device failed to return the data either because it has
gone offline or it could not respond within that time frame. If this timeout
continues to occur and the secondary is online, try increasing the Host
Command Timeout value. You should also consider that a BROADCAST
connect or disconnect takes several seconds to complete requiring a Host
Command Timeout of at least 20 seconds. The adapter must be reset each time
the dipswitch settings are changed before the changes will take effect.
Paragraph 4 provides a more detailed discussion on setting the Host Command
Timeout.
By setting an internal timer in NITP driver software, you can test for an adapter
that has lost power or a break in the connecting media between the host
computer and the adapter. The internal timer should be set to at least 100 ms
greater than the Host Command Timeout to allow the adapter to process its
time-out errors. If no message is returned within this internal time period,
check the adapter and make sure that it is online, then make sure that the
25-pin connectors are secure at the adapter's host port (Port 3) and at the host
computer, then test the media.
A–9 UNILINK HOST ADAPTER
USER MANUAL