Allen-Bradley 1756-DHRIO - Programming Terminal Port

Publication 1756-UM514B-EN-P - February 2003
Using the Data Highway Plus Network 2-3
For daisy chain configurations, use Table 2.1 to determine the
available total cable length.
For proper operation, terminate both ends of a DH+ link by using the
external resistors shipped with the 1756-DHRIO.
Table 2.2 lists the
resistors you can use with each communication rate.
Programming Terminal Port
The programming terminal connector is the same physical link as
Channel A.
Figure 2.1
Table 2.1
Choosing the Correct Cable Length
A DH+ link using this
communication rate:
Cannot exceed this cable length:
57.6 kbps 3,048m (10,000 ft)
115.2 kbps 1524m (5,000ft)
230.4 kbps 762m (2,500 ft)
Table 2.2
Choosing the Correct Resistor Rating
If your DH+ I/O link operates at: Use this resistor rating:
57.6 kbps 150W
115.2 kbps 150W
230kbps 82W
41279
Programming terminal connector
Channel A
IMPORTANT
When configuring the module switches, remember
the programming terminal connector can only be
used if Channel A is set for DH+.