Mpi/Opi Network Rules - Siemens SINUMERIK 840D sl Function Manual

Several Operator Panels on Several NCUs, Distributed Systems (B3)
2.1 Brief Description
2.1.3.4

MPI/OPI network rules

Network installations
Please take the following basic rules into account when undertaking network installations:
● The bus line must be terminated at both ends. To do this, you switch on the terminating
Note
Only two inserted terminating resistors are permitted.
In the case of HHU/HT6, bus terminating resistors are permanently installed in the
device.
● It is necessary to apply a 5 V voltage to at least 1 terminator.
● Drop cables (feeder cable from bus segment to node) should be as short as possible.
Note
Any spur lines that are not assigned should be removed if possible.
● Each MPI node must first be connected and then activated.
● Either one HHU and one HT6, or two HHUs, or two HT6s can be connected to each bus
● The following cable lengths for MPI or OPI for standard use without repeater may not be
Note
Piggy-back connectors are not recommended for power connections.
For more information about bus communication, see:
References:
/IAD/ 840D Commissioning Manual
92
resistor in the MPI connector of the first and last node, and switch off any other
terminators.
This is automatically supplied as soon as the MPI connector with the terminating resistor
fitted is connected to an activated device.
When disconnecting an MPI node, first deactivate the connection, then remove the
connector.
segment. No bus terminators must be inserted in the distributor boxes of an HHU or HT6.
If more than one HHU/HPU are connected to a bus segment, this can be done with an
intermediate repeater.
exceeded:
MPI (187.5 kbaud): Max. cable length 1000 m in total
OPI (1.5 Mbaud): Max. cable length 200 m in total
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Extended Functions