Rockwell Automation 1747-PT1, D1747NP002 Hand-Held Terminal - Manual (Page 174)

Chapter 9
Configuring Online Communication
9–10
Entering a Maximum Node Address
You may change the maximum node address for your HHT and any active
processors on the DH–485 network. However, you cannot alter the value on
another programming device. For the most efficient network operation, it is
best to set the maximum node addresses of all devices on the DH–485
network to the lowest available value.
The default maximum node address for all SLC 500 family processors and
programming devices is 31. To minimize the network scan time, it is
recommended to eliminate any unused node addresses of a higher number
than the addresses used on the network. For example, if the highest node
address used on your network is 5, then you should set the maximum node
address of all devices on the network to 5. Consequently, the polling devices
on the network no longer take the time to look for nodes 6 through 31.
Important: If you later add a device to the network with a higher node
address than the present maximum node address, you must
change the maximum node addresses to include that address.
Failure to do so causes the devices on the network to ignore the
new device.
When you cycle power to a Series A SLC 500 or SLC 5/01
processor, the maximum node address returns to the default
selection of 31.
Changing the Baud Rate
The baud rate of a processor or programming device is the speed at which it
communicates with other devices on the DH–485 network. The available
baud rates are:
•
19200 baud (default setting for all SLC 500 family devices)
•
9600 baud
•
2400 baud (not available on SLC 500 and SLC 5/01 processors)
•
1200 baud (not available on SLC 500 and SLC 5/01 processors)
You do not need to cycle power if you change your HHT baud rate. The
baud rate changes as soon as you press
[ENTER] .
Important: The baud rate change to a processor does not take effect until
power is cycled to the processor.
Set and Clear Ownership
The set and clear ownership function allows a terminal to “own” one or more
processor files on the network. Ownership means that as long as the owner
is active on the network, other terminals cannot access the online functions
of the owned processor files. Only a programming device can own a
processor.