Siemens SIMATIC TIWAY 1 - Manual (Page 89)

HOST COMMAND SET REFERENCE
UNILINK HOST ADAPTER 5–4
USER MANUAL
The cycle at power-up or reset is shown in Figure 5–2.
Configuration
Initiation
Operation
Performance
Termination
Figure 5–2 Command Usage Cycle
5.1.3 Secondary Addresses
Secondary addresses are one byte in length and range from 1 to 254. The
addresses 0 and 255 are reserved for special functions as indicated in Table 5–1.
Normally the address 255 is used as a shorthand method to indicate that the
command should be processed for all secondary devices on the network. Care
must be used with this shorthand method because a host command timeout may
occur before the response has been gathered from all of the secondaries.
Your network will operate more efficiently if you number your secondary
devices and HIUs beginning with address “1” and consecutively numbering the
remaining devices.