User manual

Digital Monitor AMC-1DBx Series User Manual

SENSOR/

TRANSMITTER:

Refer to section 4.1.2.2 RS-485.

ANALOG

OUTPUT:

Refer to section 4.1.2.12 Analog Outputs

5.2.2

Cable Selection

The wiring consists of two subsystems:

• the monitor communication

• power supply wiring

A cable is used to connect the RS-485 signals from the digital monitor to digital

transmitters in a bus topology. It is required that shielded, twisted pair, cable, 120 ohm

impedance is used for the communications wiring. This bus can be up to 1 Km (1092

yards) in length.

Power supply wiring requires two conductors (+24VDC and SGND). The length of the

power supply wiring is dictated by the voltage drop in the wiring. Using thicker wire

results in longer distances.

For best signal transmission and maximum noise rejection, run the cable through a steel

conduit (the cable shield must be grounded at the monitor).

WARNING

ALL CABLES MUST PASS THROUGH CONDUIT SEALS INSTALLED

BETWEEN THE HAZARDOUS (CLASS I, DIVISION 1 OR 2) AND NON-

HAZARDOUS AREAS FOR SAFETY REASONS AND TO COMPLY WITH

THE LOCAL MUNICIPAL, PROVINCIAL, STATE, OR FEDERAL

ELECTRICAL REGULATIONS.

FOR UL ONLY (U.S.), FOLLOW THE NATIONAL ELECTRICAL CODE

(NFPA 70) AND THE AUTOMOTIVE & MARINE SERVICE STATION

CODE (NFPA 30A0.

5.3 ALARMS

Alarm detection for each sensor input may be individually programmed to operate in one

of four modes: alarms disabled, alarm thresholds on increasing concentration, alarm

thresholds on decreasing concentration, and windowed alarm (high/low) operation.

Up to three alarm thresholds may be configured for each sensor input (two thresholds for

windowed operation). Each alarm threshold is individually adjustable in increments of %

full scale.

An adjustable hysteresis value is applied to alarm detection. This hysteresis is provided

to prevent multiple alarms and relay oscillation should a sensor level remain near the

threshold setting. The hysteresis level is adjustable from 0 to 5% of full scale in 0.1%

increments at the system level for all sensors simultaneously.