Allen-Bradley SLC 500 Manual

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• Allen-Bradley QUICKDESIGNER
Additional Information
Network Performance
The following are major configuration factors that have a significant effect on network performance:
• The number of nodes on the link
• The addresses of those nodes
• The maximum node address selection
The number of nodes on the link directly affects the data transfer time between nodes. Unnecessary
nodes slow the data transfer rate. The maximum number of nodes on the link is 32.
The best link performance occurs when node addresses start at 0 and are assigned in sequential order.
Also, initiators such as personal computers should be assigned the lowest numbered addresses to
minimize the time required to initialize the link. If all nodes are expected to be connected at all times,
this is really all you need to do.
The maximum node address parameter should be set as low as possible. This minimizes the amount of
time used in soliciting successors when initializing the link. If all nodes are addressed in sequence from
0, and the maximum node address is equal to the address of the highest addressed node, the token
rotation will improve by the amount of time required to transmit a solicit successor packet plus the slot
timeout value.
NOTE - The SLC500 processors set the maximum node address to 31 when power is cycled increasing
initialization and response time of the link.
DH-485 Cable
The suggested DH-485 communication cable is BELDEN #9842 cable. The cable is jacketed and
shielded with two twisted wire pair and a drain wire.
DH-485 Connections
One (only one) of the Link Couplers at the end of the link must have Terminals 1 and 2 of the link
connector jumpered together. This provides an Earth Ground connection for the shield of the
communications cable.
Link Couplers at both ends of the link must have Terminals 5 and 6 of the link connectors jumpered
together. This connects the termination impedance that is built into each link coupler as required by the
DH-485 specification.
6 - TERM
5 - A
4 - B
3 - COMMON
2 - SHIELD
1 - CHS GND
Allen-Bradley SLC 500 DF1

Allen-Bradley SLC 500 Specifications

General

Programming Software	RSLogix 500
Communication Ports	RS-232, DH-485, DH+
Power Supply	120/240V AC or 24V DC
Programming Languages	Ladder Logic
Operating Temperature	0°C to 60°C (32°F to 140°F)
Relative Humidity	5% to 95% (non-condensing)
Memory	4K to 64K words (depending on the processor)