06.03
5.6 Handheld unit (HHU)
5-153
Siemens AG, 2003. All rights reserved
SINUMERIK 840Di Manual (HBI) – 06.03 Edition
5.6.2
Electrical connection
In order to connect HHU electrically and for communication along the MPI bus,
a distributor box is used.
The distributor box has an interface to the MPI bus, as well as a terminal block
for connecting EMERGENCY STOP, enable keys, handwheel and 24V power
supply.
If you wish to connect more than two HHUs to a bus segment or if the HHU can-
not be connected at the bus end, it is generally recommended to use a PROFI-
BUS repeater for connecting the HHUs.
ON
OFF
OFF
OFF
ON
ON
ON
SINUMERIK
840Di
HHU
Distributor box
MPI
Closed terminating resistor
Open terminating resistor
ON
MCP
Repeater RS-485
HHU
Fig. 5-9
Connecting using a repeater
Note
If a HHU is connected to the bus ends, no repeater is required.
For a detailed description of the electrical and mechanical design, as well as for
the interfaces of the HHU module, please refer to:
References:
/BH/
Operator Components, Manual
Section: Handheld Unit and Distributor Box.
Connecting the
HHU electrically
Connecting
several HHUs
5 MPI Communication
