Siemens SIMATIC TIWAY 1 - Manual (Page 17)

OPERATION AND APPLICATION
UNILINK HOST ADAPTER 2–7
USER MANUAL
The following operational modes include the NM function. However, the
MHIU/EHA mode does not provide access to the NM command set.
D Master Host Interface Unit (MHIU)
D Network Manager (NM)
D Standalone Network Manager (SANM)
D Master Host Interface Unit/Emulate Host Adapter (MHIU/EHA)
2.3.3 The Master Host Interface Unit Mode
The Master Host Interface Unit (MHIU) is a combination of the HIU and NM
functions as shown in Figure 2–6. A host computer connected to an MHIU can
communicate with secondary devices through the HIU function and control
network performance through the NM function. Remember, only one adapter in
a TIWAY I network may have the NM function.
HIU NM
MHIU
Figure 2–6 Master Host Interface Unit Diagram