Impulse PCW-5181 Daisy-Chaining Impulse Drives, Multi-Dropping with RS-485

Chapter 3 - Connecting and Installing Your Impulse
3-5
Daisy-Chaining Impulse Drives
Your Impulse also supports daisy chaining. The unit ad dres s (ran ge 1 -99 ) can be s et via the k eyp ad
or in Application Developer.
Rules for Daisy Chain Operation
1. Units on a daisy chain mu st be “d evice add res sed’ (nu mber ed) in o rder for communications to
work properly. A unit’s address should increment upward as you move down the daisy chain
from the PC (see illustration below).
2. Do not duplicate unit addresses.
3. Any loose RS-232C connections or miswiring along the daisy chain will cause communications
to fail. Please double check wiring if communication problems arise.
4. Please call IDC if you need to daisy chain more than 99 drives.
5. The hardware diagram below shows how to connect the daisy chain.
Multi-Dropping with RS-485
If you will be “multi-dropping” Impulse drives with RS485, add 120-ohm termination resistors
across RX and TX connections of the last unit as shown below:
RX TX COM RX TX COM RX TX COM
RX
TX
COM ..
Impulse
Unit 1 Unit 2 Unit 3
PC/Host
RS-232C
Device
Impulse
Impulse
RS-485
Host
Add resistors as
shown here: