EIA-485 wiring | Marathon Computer AACC 2000 instruction

		Marathon Monitors Inc.
Wiring of 2-wire EIA-485 serial communications link
	PC
		2-wire EIA-485 is a connection which allows up to 32
Com	TX	controllers to be multi-dropped from a single
Com	TX	RX
Local		communications link over a distance of up to 1.2Km.
Local		To ensure reliable operation of the communications
Earth		To ensure reliable operation of the communications
232		link, (without data corruption due to noise or line
232		reflections) the connections between the controller
		reflections) the connections between the controller
Local		should be made using a twisted pair of wires inside a
Local		screened cable with the connections terminated with
Earth	RX	screened cable with the connections terminated with
Com	RX	TX
		resistors in the manner shown in this diagram.
MMI Universial
	Converter
Com	B	A

		A	HE -
		B	HE -	Series 2000
		B	HF+	Series 2000
		Com	HF+	Controller
		Com	HD	Controller
			HD
	Local
	Earth
	Local			Local	Local
	Ground			Ground	Ground
	Zone 1			Ground	Ground
	Zone 1			Zone 1	Zone 2
				Zone 1	Zone 2
	Local			A
	Earth	A		A	A	HE-
	Earth	A	Galvanic	B	A	HE-	Series 2000
		B	Galvanic		B
	Local		Isolation		B	HF+
	Local		Isolation			HF+	Controller
	Ground	Com	Barrier Com		Com		Controller
	Ground	Com	Barrier Com		Com	HD
	Zone 1					HD

Local
Earth				Local Earth
Local
Ground
Zone 1	Up to 32 S2000 controllers or			For reasons of safety
	Up to 32 S2000 controllers or			do not connect to
	Interface Units may			do not connect to
Local	be included on the network			local earth here.
Earth
	A	HE-	Series 2000
	B	HE-
	B	HF+
	Com	F	Controller
Area 1	Com	HD
Area 1		HD

Note:

All resistors are 220 ohm 1/4W carbon composition.

Local grounds are at equipotential. Where equipotential is not available wire into separate zones using a galvanic isolator.

Use a repeater (KD845) for more than 32 units.

Figure 1-9 EIA-485 wiring

AACC 2000 Carbon	21	Nov. 1, 1997
	21

Image 21

Marathon Computer AACC 2000 manual Wiring of 2-wire EIA-485 serial communications link, EIA-485 wiring

Contents

Copyright Marathon Monitors INC Marathon Monitors Inc Mechanical Installation Electrostatic discharge precautions SafetyCleaning Electromagnetic compatibility Wiring Safety SymbolsPower Isolation Personnel Overcurrent protection Over-temperature protectionVoltage rating Conductive pollution Installation requirements for EMC Grounding of the temperature sensor shieldRouting of wires Equipment ratings Environmental ratings General Electrical safety Marathon Monitors Inc Installation Outline dimensions Model 2000 controller Outline dimensions Model Introduction To install the controllerController labels Unplugging and plugging-in the controller Model Aacc 2000 rear terminal layout Rear terminal layouts Marathon Monitors Inc Module 1, 2 Sensor input connections Snubbers Two terminal modules Four terminal modules COMDual output modules Connections for Process Value 2 PV2 Connections for Process Value 3 in module position Communication module EIA-485 wiring Wiring of 2-wire EIA-485 serial communications link Marathon Monitors Inc Operation Front Panel LAYOUTs 26.0 OP1 Button or Name ExplanationOP2 SP2 Basic operation Alarms Operating modes Output power demand Automatic modeHome display Display units Setpoint Manual Mode List header displays Parameters and HOW to Access Them Marathon Monitors Inc Parameter names Parameter displaysTo change the value of a parameter List 1OFFOFF PID.1 PID STD Fact Pass Name Description Prob Probe list Process Factor Millivolt input OffsetHydrogen or CO constant Name Description DrA TunEDrA.t Adc SEt Pid PID listRES Hcb Input list Setpoint list Output list CmS Comms listInFo Information list FF.OP Access List Alarms Display What it means What to do about it Shows Diagnostic alarms 2b Diagnostic alarms Access Levels Access list header Password entryAccess to Read-only Configuration Configuration password Configuration levelLevel selection Edit level Setting operator access to a parameterReturning to Operator Level Hiding or revealing a complete list Promoting a parameter This sheet intentionally left blank Parameter Code Meaning or Function Tuning How to tune One-shot Tuning Typical automatic tuning cycle Calculation of the cutback valuesAdaptive tune Manual Tuning Proceed as follows Setting the cutback values Automatic droop compensation Adc Integral action and manual reset Motorized valve control Name Description Values Mtr Motor list Min Max Default Inertia and backlash settings Adjusting the minimum on-time ‘mp.t’ Marathon Monitors Inc Enable in configuration level Gain schedulingSet the transfer point Configuration Press to enter configuration Selecting configuration level Changing the passwords Leaving Configuration Level LIN REUD1SA Enab SB.OP Rely CMSNone YES DIG PMV Name Description Values Meaning InSt Instrument configurationH2O SP.FF Process value config Input configurationCJC Setpoint configuration VAL.LVAL.H Alarm configuration Values Table a Alarm types ValueAlarm Modes Digital input 1 configuration Action on contact closure Digital input 2 configuration Action on contact closureIMP Alarm relay configuration VfltPflt Combining several digital events on to one output Comms 1 module config Module config 1A b C1 Module 1 configurationCool For ‘id’ = ‘LoG.i’ i.e logic input use the LA Conf’ list on 2A/b/C Module 2 configuration Displayed value low SEL 3A/b/C Module 3 configuration Module configuration C Module configuration Point Custom Linearisation VAL.1VAL.8 CAL Exit Exit configuration Password configurationDC Output Calibration User calibration User calibration Calibration Configuration List User Calibration EnableUser Calibration Enable Exit configuration Offset calibration Input list headerCalibration type Set Offset See table on the right for additional parameters Displayed Value Two-point calibration Select Low-point Calibration Adjust low-point calibration Select High-point Calibration Adjust High-point Calibration Name Parameter description Meaning Calibration points and Calibration offsets Parameter Table Default HY1 Ssel FLT3 Marathon Monitors Inc AL1 Module 2A High Value VAL.1 101 Index Two-point calibration User calibration Aacc 2000 Carbon