Siemens SIMATIC TIWAY 1 - Manual (Page 144)

HOST COMMAND SET REFERENCE
UNILINK HOST ADAPTER 5–59
USER MANUAL
0 1 2 3 4 5 6 7
Not used
1 = HIU Allocated NM Buffers
1 = Secondary Is An HIU
1 = Secondary Has Been Identified
0 = Secondary Has Not Been Identified
1 = Secondary Is On–Line
1 = Current Channel Is B
1 = Channel B Available
1 = Channel A Available
0 = HIU Has Not Been Alocated NM Buffers
0 = Secondary Is Not An HIU
0 = Secondary Is Off–Line
0 = Current Channel Is A
0 = Channel B Not Available
0 = Channel A Not Available
MSB LSB
Figure 5–11 Link Status Byte Bit Map
Bit–0 When set to one, indicates that the Network Manager can
communicate with the secondary device on Channel A (Port 1).
Bit–1 When set to one, this bit indicates that the Network Manager can
communicate with the secondary device on Channel B (Port 2).
Bit–2 This flag indicates which channel the Network Manager is
currently using to communicate with the secondary device.
When set to one, the NM is communicating on Channel B. When
set to zero, the NM is communicating on Channel A.
Bit–3 Background monitor will automatically bring secondary devices
online. However, these secondary devices are not available to the
host until they are connected with the CONNECT SECONDARY
command. When set to one, this bit indicates that background
monitor has brought the secondary device online.
Bit–4 When set to one, this bit indicates that Background Monitor has
determined that the secondary device can request network
transactions.
Bit–5 When set to one, this bit indicates that the secondary device is an
HIU in a multi-host network. Bit–4 must also be set to one before
the value of this bit is valid.
Bit–6 When set to one, this bit indicates that the HIU has been allocated
NM buffers by the NM. It can now request network transactions.
Bit–7 Reserved.