EasyManuals Logo

Honeywell Touchpoint 4 User Manual

Honeywell Touchpoint 4
18 pages
To Next Page IconTo Next Page
To Next Page IconTo Next Page
To Previous Page IconTo Previous Page
To Previous Page IconTo Previous Page
Page #16 background imageLoading...
Page #16 background image
Touchpoint 4 Serial Communication Protocol Issue 1 09/07
Topology
Touchpoint4 Serial Communication system has one trunk cable, along which devices
are connected, directly (daisy chaining) or by short derivation cables.
Thetrunkcable,alsonamed“Bus”,canbelong(seehereafter).Itstwoendsshouldbe
connected to Line Terminations.
Length
Theend-to-endlengthofthetrunkcablemustbelimited.Themaximumlength
depends on the baud rate, the cable (Gauge, Capacitance or Characteristic Impedance),
and the quantity of loads on the daisy chain.
Foramaximum9600BaudRateandAWG26(orwider)gauge,themaximumlength
is1000m.
If the derivation cable is needed for the connection of the master, the derivation must
beshort,nevermorethan20m.
Grounding Arrangements
At one end of each cable its shield must be connected to protective ground.
Line Termination
To minimize the reflections from the end of the RS485-cable, it is recommended to
place a Line Termination near each of the 2 Ends of the Bus.
It is important that the line must be terminated at both ends since the propagation
isbi-directional,butitisnotallowedtoplacemorethan2LTononepassiveD0-D1
balanced pair. Never place any LT on a derivation cable.
Each line termination must be connected between the two conductors of the balanced
line:D0andD1.
Lineterminationmaybearesistorof100ohmsto150ohms(0.5W).
Pull-up and Pull-down Resistors
Line control has been implemented in Touchpoint4 gas detector controller so that the
buscontainsavalid"off"signalwhennonodeistransmitting.Noexternalpull-upor
pull-down resistors are needed.
13

Questions and Answers:

Question and Answer IconNeed help?

Do you have a question about the Honeywell Touchpoint 4 and is the answer not in the manual?

Honeywell Touchpoint 4 Specifications

General IconGeneral
BrandHoneywell
ModelTouchpoint 4
CategoryGas Detectors
LanguageEnglish

Related product manuals