HEIDENHAIN MANUALplus 620 Technical Manual page 1761

9.3 HSCI interface
January 2012
The individual control components communicate with each other via the HSCI
connection (HEIDENHAIN Serial Controller Interface). At this time a
connection via HSCI is only permitted for HEIDENHAIN components that are
part of the machine tool's control system. In addition, the HSCI connecting
cable may only be installed in a protected manner (e.g. within the electrical
cabinet, cable ducts).
The following features characterize the HSCI connection:
Based on standard 100BaseT Ethernet hardware
Telegrams of the HSCI connection are not compatible with the Ethernet
Line structure
No collisions
Data-transfer cycle (HSCI cycle): 3 ms
Jitter less than 1 ns
Only one master in the system (MC), all other devices are HSCI slaves
Slave-to-slave communication possible
HSCI master must initiate every data transfer
Realization with FPGAs
Different addresses are assigned to the individual participants in the HSCI
network. The addresses are assigned dynamically during booting of the MC.
The HSCI addresses of the participants are formed from a bus address (8 bits)
and a device type address (6 bits).
After the machine has undergone acceptance testing, the nominal
configuration of the machine is saved on the control's hard disk. This nominal
configuration contains the association between the device-type address and
serial number of the device to the individual bus addresses. The momentary
configuration is ascertained during startup of the system by requesting the
serial numbers. The momentary configuration is compared with the nominal
configuration. If there is a deviation, the machine operator is prompted to
check the configuration.
The following applies to the assignment of the bus address:
The bus address is the result of the device's position in the bus
The master (MC) always has the bus address 0
The bus addresses of the slaves result from their position in the bus:
• First device after the master (MC): Bus address 1
• Second device after the master (MC): Bus address 2
• etc.
The bus address 0xFF is used as multicast address
9.3 HSCI interface 1761