AMC AMC-1228 - User Manual

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Overview

Function Description
Important Technical Specifications
Usage Features
Maintenance Features

The AMC-1228 Multidrop is an electrochemical sensor module designed for continuous surveillance of hazardous gases in the surrounding air. It is intended for use with Multidrop AMC monitors and can be interconnected in a "daisy chain" configuration with other sensor modules.

Function Description:

The AMC-1228 sensor unit provides continuous, reliable surveillance of surrounding air for traces of hazardous gases. It is designed to allow interconnection in series (daisy chain) to a single or multi-channel AMC 1AD Series monitor or other AMC monitors with equipped inputs. A maximum of eight (8) sensor modules can be connected to each zone. The units can also be branched out from the central line, offering maximum flexibility. Each unit produces Low alarm, High alarm, and sensor Fail signals, which are transferred from one sensor to the next up the line back to the monitor.

Important Technical Specifications:

Sensor Module Part Number: (To be filled in by user)
Sensor Module Serial Number: (To be filled in by user)
Sensor Element Part Number: (To be filled in by user)
Sensor Element Serial Number: (To be filled in by user)
Sensor Warranty Period: (To be filled in by user) years
Wire Gauge: 18 AWG @ 150 ft max between units
Power Supply Requirement: 6 to 18 VDC
Operating Temperature: 0° to 40° C
Operating Pressure: Ambient atmospheric pressure
Relative Humidity: 0 to 99% RH, non-condensing
Gas Type: (To be filled in by user)
Low Alarm Setting: (To be filled in by user)
High Alarm Setting: (To be filled in by user)
Calibration Adapter Part Number: (To be filled in by user)

Usage Features:

Internal Features: Each sensor module features alarm indicators, adjustment trimmers, and connection terminal blocks.
- Sensor: Electrochemical cell, factory calibrated.
- High Alarm Indicator: Red LED indicates high gas conditions.
- Low Alarm Indicator: Yellow LED indicates low gas conditions.
- Power/Fail Indicator: Illuminated green LED indicates power. A sensor failure causes the green LED to turn OFF.
- High Alarm Adjustment: Sets the high alarm trip point.
- Low Alarm Adjustment: Sets the low alarm trip point.
- Signal Adjustment: Sets the sensitivity of the sensor.
- Terminating Jumpers: Jumper clips are supplied installed on the circuit card. When connecting additional sensor modules, the jumper clip corresponding to the terminal block must be removed.
- Output Terminal Block (TB3): Connects to the monitor or to the input terminals of another sensor module.
- Input Terminal Blocks (TB1, TB2): Used to connect additional sensor modules. Each unused input terminal block must be locked-out using a terminal jumper.
Installation: The sensor unit should be mounted on a solid, non-vibrating surface, easily accessible for status checking and calibration, in an area where local gas concentration is unaffected by ventilation systems. Mounting hardware is not supplied.
Cable Selection and Wiring: Connection should be made using 3-conductor, shielded cable (shield grounded at the monitor) through steel conduit for best signal transmission and maximum noise rejection. A maximum length of 150 feet of 18 AWG size cable is allowed between each unit and between the monitor and the first unit(s).
Multi-Unit Interconnection: Sensor modules can be interconnected in series and/or branching configurations. Because each unit is pre-calibrated, additional units can be added without altering monitor settings. When multiple units are interconnected, either one or both jumpers need to be removed from the input terminal blocks.
Termination: For each unused input terminal block, the corresponding jumper MUST be left installed to prevent system malfunction.
Operation: After stabilization in a clean air environment, the sensor module should display a GREEN Power ON LED.
- Alarm Conditions: If gas exceeds the LOW alarm trip point, the yellow LED turns ON on the unit and the monitor. If gas exceeds the HIGH alarm trip point, the red LED turns ON.
- Fault Supervision: The AMC-1228 is equipped with fault detection circuitry, indicated by the green Power LED turning OFF. The fault condition persists until corrected.
Calibration: The sensor module is factory calibrated. Recalibration is necessary when replacing the sensor or changing alarm trip point settings.
- Span Adjustment: Adjust signal voltage to proportional calibration gas concentration using the Span Adjust Trimmer. Signal is measured from TB3 (-) to a 20K resistor.
- Alarm Adjustment: Adjust the corresponding Alarm Voltage to the appropriate fraction of full-scale gas concentration using the High or Low Trimmer. Alarm Voltage can be measured from TB3 (-) to the Low test point and High test point.
High Alarm Latching Option (Addendum):
- Overview: This option provides a latching alarm level of gas overnight or for other unattended periods. The latching option includes the AMC Multidrop, latching module, the latching LED, and the reset switch.
- Operation: The unit operates as per a standard Multidrop with the additional feature. When there is a high alarm, the latching high alarm red LED will turn ON and stay on. To turn this LED OFF, the reset button has to be pushed.
- Latching Module Specifications:
  - Power – Non alarm: 5 VDC @ 2 uA
  - Power – Alarm: 5 VDC @ 7 mA
  - Operating temperature: -10 to +40 °C
  - Wiring to Multidrop PCB: Red (+), yellow (signal), green (ground)
  - Wiring to reset switch: Brown, brown
  - Wiring to latching LED: Black, orange

Maintenance Features:

General: The sensor unit should be brushed or wiped clean annually or more frequently, depending on dust or dirt accumulation. The unit should NOT be submerged or placed under conditions where water or other liquids could enter the transmitter.
Verification of Operation: Verification of operation and calibration should be done at least once every 6 months for safety reasons; monthly verification is recommended for highly demanding applications.
Sensor Replacement: The sensor should be replaced when the green LED turns OFF while the unit is powered, or when the sensor no longer adequately responds to test gas.
- To replace the sensor element, remove the four screws and cover plate from the housing. Unplug the used sensor element from its socket and discard, then plug in the replacement sensor element. Reinstall the cover plate and screws.
- Allow 24 hours for the new sensor element to stabilize (burn-in) before recalibration.

AMC AMC-1228 Specifications

General

Brand	AMC
Model	AMC-1228
Category	Control Unit
Language	English