AMC 350 User manual

350
Sensor/Transmitter
INSTRUCTIONS
Installation, Calibration & Maintenance
of the AMC-350 Sensor/Transmitter
IMPORTANT:
Please read these installations and operating instructions completely
and carefully before starting.
Filename; Manual_amc-350_transmitter.doc Revised, 7/21/2004 Copyright ©, April 1989, AMC
The Armstrong Monitoring Corporation
215 Colonnade Road South, Nepean, Ontario, Canada K2E 7K3
Tel: [phone] • Fax: [phone] • Canada & U.S. Toll Free: 1-800-465-5777
E-mail: [email protected] • Internet: www.armstrongmonitoring.com/gas/

AMC-350 Sensor/Transmitter
1
TABLE OF CONTENTS
Section Title Page
1WARRANTY.............................................................................................................3
1.1 LIABILITY...........................................................................................................3
1.2 PRODUCT RETURN .........................................................................................3
1.3 MODIFICATIONS AND SUBSTITUTIONS.........................................................3
2PRODUCT INFORMATION......................................................................................4
2.1 SENSOR/TRANSMITTER..................................................................................4
2.2 FACTORY SETTINGS.......................................................................................4
3PRODUCT DESCRIPTION ......................................................................................5
3.1 GENERAL DESCRIPTION.................................................................................5
3.1.1 SENSOR / TRANSMITTER SPECIFICATIONS......................................................5
3.2 HOUSING OPTIONS.........................................................................................6
4INSTALLATION .......................................................................................................7
4.1 LOCATION AND MOUNTING............................................................................7
4.2 CABLE SELECTION AND WIRING...................................................................8
4.3 COMPUTER, DATALOGGER OR NON-AMC INTERFACE..............................9
5OPERATION AND CALIBRATION........................................................................11
5.1 OPERATION....................................................................................................11
5.2 CALIBRATION.................................................................................................11
5.2.1 EQUIPMENT REQUIRED.....................................................................................11
5.2.2 TRANSMITTER CALIBRATION/VERIFICATION PROCEDURE..........................12
5.2.3 RECALIBRATION .................................................................................................12
6PREVENTIVE MAINTENANCE..............................................................................14
6.1 GENERAL........................................................................................................14
6.2 VERIFICATION OF OPERATION....................................................................14
6.3 SENSOR REPLACEMENT..............................................................................14

AMC-350 Sensor/Transmitter
2
NOTE
This page intentionally left blank.

AMC-350 Sensor/Transmitter
3
1WARRANTY
The AMC-350 Series Transmitter is warranted against defects in material and workmanship for
a period of two (2) years from date of delivery. During the warranty period, The Armstrong
Monitoring Corporation will repair or replace components that prove to be defective in the
opinion of AMC. We are not liable for auxiliary interfaced equipment, or consequential damage.
This warranty shall not apply to any product, which has been modified in any way, which has
been repaired by any other party other than a qualified technician or authorized AMC
representative, or when such failure is due to misuse or conditions of use.
1.1 LIABILITY
All AMC products must be installed and maintained according to instructions. Only qualified
technicians should install and maintain the equipment. AMC shall have no liability arising from
auxiliary interfaced equipment, for consequential damage, or the installation and operation of
this equipment. AMC shall have no liability for labour or freight costs, or any other costs or
charges in excess of the amount of the invoice for the products.
THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED,
AND SPECIFICALLY THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
PARTICULAR PURPOSE. THERE ARE NO WARRANTIES THAT EXTEND BEYOND THE
DESCRIPTION ON THE FACE THEREOF.
WARNING
CHECK TO ASSURE THE WORKING AREA IS FREE FROM HAZARDS DURING
INSTALLATION OR WHEN PERFORMING MAINTENANCE, AND USE PROPER
PRECAUTIONS.
1.2 PRODUCT RETURN
All products returned for warranty or service should be shipped by prepaid freight and will be
accepted only with a repair number issued by AMC. All products returned to the client will be
shipped by freight collect.
1.3 MODIFICATIONS AND SUBSTITUTIONS
Due to an ongoing development program, AMC reserves the right to substitute components and
change specifications at any time without incurring any obligations.

AMC-350 Sensor/Transmitter
4
2PRODUCT INFORMATION
2.1 SENSOR/TRANSMITTER
Sensor/Transmitter Unit Order Number..………………………..
Transmitter Part Number…………..……………..……………….
Transmitter Serial Number………...………………………….……
Sensor Part Number…………………………………………….…..
Sensor Serial Number ………….…………………………………..
Power Supply Requirement ………………………………………. 12 to 26 VDC @ 250 mA
Signal Output Load ……………………………………………….. maximum 250 ohms
Sensor Warranty ……………………………………………….. _______________________
2.2 FACTORY SETTINGS
Gas Type. ……………………………………………………………
Range. ……………………………………………………………….
Zero Gas, at 4 mA signal……………………………………………
Gas Concentration at 20 mA signal ………………………………
Calibration Adapter Part Number………………………………….
Note:
All Armstrong Monitoring systems must be installed and maintained according to
instructions to assure proper operation. Only qualified technicians should install and
maintain the equipment.

AMC-350 Sensor/Transmitter
5
3PRODUCT DESCRIPTION
3.1 GENERAL DESCRIPTION
The AMC-350 series sensor/transmitter unit is designed to provide continuous, reliable
surveillance of surrounding air for traces of hazardous gases (listed in Factory Calibration,
section 2.2). It provides a 4 to 20 mA, variable current signal, which is proportional to the gas
concentration detected. Each sensor/transmitter unit is factory calibrated and ready for field
installation and operation.
3.1.1 SENSOR / TRANSMITTER SPECIFICATIONS
SENSOR TYPE:
Solid state.
RESPONSE TIME:
90% full scale in less than 30 seconds.
ZERO DRIFT:
Less than 5% per year.
SIGNAL OUTPUT LOAD:
250 Ohms maximum.
OPERATING TEMPERATURE:
-40 to +40 ºC (-40 to +104 ºF)
HUMIDITY:
0 to 99% RH, non-condensing.
OPERATING PRESSURE:
Ambient atmospheric pressure.
EXPECTED SENSOR LIFE
10 years (continuous operation).
ACCURACY/REPEATABILITY
Within 5% of full scale.
Note:
Turn off power supply before removing or replacing the transmitter or sensor.

AMC-350 Sensor/Transmitter
6
3.2 HOUSING OPTIONS
The AMC-350 series sensor/transmitter units are available in the following housings (see
FIGURE 1). The explosion-proof housings are also available with a corrosion resistant finish.
•Explosion-Proof (rated for Class I, Groups B, C, D)
•Explosion-Proof (rated for Class I, Groups A, B, C, D)
FIGURE 1: Explosion-proof housing options.

AMC-350 Sensor/Transmitter
7
4INSTALLATION
4.1 LOCATION AND MOUNTING
Mount the sensor/transmitter unit on a solid, non-vibrating surface or structure in an area where
the local concentration of gas is unaffected by the presence of ventilation systems. The
sensor/transmitter housing SHOULD NOT touch the mounting surface. In some cases this may
require the use of a spacer between the mounting surface and the sensor/transmitter housing.
(See FIGURE 2).
Note:
Mounting arrangement of the transmitter housing depends on location of transmitter
and mounting surface. Mounting hardware is not supplied.
FIGURE 2: Mounting of the sensor/ transmitter.

AMC-350 Sensor/Transmitter
8
4.2 CABLE SELECTION AND WIRING
The transmitter output (–, S, +) terminal block connects to the (–, S, +) connections on a
channel terminal block of the monitor (one transmitter per channel), as shown in FIGURE 4.
Connection should be made using 3-conductor, shielded cable (shield must be grounded at the
monitor). Run cable through steel conduit for best signal transmission and maximum allowable
distances. The maximum permissible distance between the transmitter and monitor is
dependant on wire gauge as shown in the following Cable Selection Chart (FIGURE 3)
FIGURE 3: Cable Selection Chart.

AMC-350 Sensor/Transmitter
9
FIGURE 4: Transmitter wiring layout.
4.3 COMPUTER, DATALOGGER OR NON-AMC INTERFACE
Refer to FIGURE 5 for the following.
All Armstrong sensor/transmitter units can be interfaced with computers or dataloggers through
analog-to-digital converters.
The signal output from the transmitter is a 4 to 20 mA DC current. This can be measured from
the signal wire, or if a voltage measurement is needed, connect a load resistor (250 ohms max)
between the transmitter signal output (S) and power supply ground (–).

AMC-350 Sensor/Transmitter
10
FIGURE 5: Interface to computer, datalogger or non-AMC monitor.

AMC-350 Sensor/Transmitter
11
5OPERATION AND CALIBRATION
5.1 OPERATION
The AMC-350 series sensor/transmitter unit is factory calibrated for the gas listed in Product
Information (section 2). The unit should not need recalibration when first installed and powered
up, but a test for correct operation is recommended. All testing should be done after a
stabilization period.
In general, after the stabilization period, the transmitter should be sending (in a Zero gas
environment) a signal of approximately 4 mA to the monitor or controller. However, there are a
few situations where a slightly higher or lower than normal signal may be noticed. In many
facilities there can be residual levels of the gas being detected in the air at all times. These can
cause a minor response from the sensor, normally causing a rise in signal. Other causes for
minor signal variations include extremes in temperature. In the case of large signal variations
(in a clean environment), check for an installation problem.
5.2 CALIBRATION
The sensor/transmitter is equipped with a remote calibration feature allowing one-man
calibration at the transmitter location. The transmitter output is measured using a plug-in type
“Remote Calibration Lead” designed to be adaptable to most multimeters. Zero and span
adjustments are made at the transmitter. Recalibration is necessary when replacing the sensor.
Verification of calibration should be done at least once every 6 months for safety reasons and
for highly demanding applications, monthly verification is recommended.
Factory/on-site calibration services, customer training and/or calibration adapter are available.
Specify the sensor/transmitter Part Number & Serial Number listed in section 2.1
SENSOR/TRANSMITTER and refer to section 2.2 FACTORY CALIBRATION for Gas Type and
calibration adapter when ordering any of the above.
Caution:
- Only qualified personnel should perform the actual calibration.
- Users are advised to consult The Armstrong Monitoring Corporation as to the
calibration procedure and recommended gas concentration for the application.
5.2.1 EQUIPMENT REQUIRED
•Digital multimeter
•Remote Calibration Lead (provided with the transmitter)
•Trimmer adjustment tool or miniature screwdriver
•Calibration adapter
•Zero & Span gases and Permeation tube (Contact factory for information)

AMC-350 Sensor/Transmitter
12
5.2.2 TRANSMITTER CALIBRATION/VERIFICATION PROCEDURE
The calibration procedure may cause the monitoring equipment to give a false alarm; therefore
appropriate precautions should be taken. Instructions for introducing the gas sample are
included with every Calibration Kit or available separately on request (depending on type of gas
or application). Refer to FIGURE 6 for the Calibration/Verification setup.
1. Remove cover from transmitter housing.
2. Connect “Remote Calibration Lead” to multimeter. BLACK lead to negative or common
(–). RED lead to positive (+) on mA scale.
3. Switch ON multimeter and select a DC milliamp range greater than 20 mA full scale.
4. Insert plug end of “Remote Calibration Lead” fully into CAL jack on transmitter cover
plate.
5. Apply a Zero gas sample or with the sensor in clean air or while covering the open end
of the sensor, check for a stabilized zero signal of approximately 4 mA.
6. Apply a Span gas sample. Since the transmitter output range is 4 to 20 mA, a full-scale
concentration should register 20 mA after a few moments exposure.
5.2.3 RECALIBRATION
There are two adjustments to be made for periodic recalibration: Zero and Span.
Zero: With the sensor in Zero Gas, the transmitter output signal current should read 4 mA.
This is obtained by adjusting the Zero trimmer on the transmitter for a voltage of
0.000 VDC at the test points in Figure 6. It is possible, under certain conditions that
the Zero current will fall below 4 mA.
Span: While the sensor is exposed to the calibration gas sample, adjust the Span trimmer on
the transmitter to set the transmitter output signal current proportional to the applied
gas concentration.

AMC-350 Sensor/Transmitter
13
FIGURE 6: Calibration/Verification Set-up.

AMC-350 Sensor/Transmitter
14
6PREVENTIVE MAINTENANCE
6.1 GENERAL
The sensor/transmitter unit should be brushed or wiped clean once a year or more, of any dust
or dirt, which settles on it, depending on the accumulation.
The unit SHOULD NOT be submerged in water or other liquids. Also, hosing and other
conditions that could cause a liquid to enter the enclosure should be avoided.
6.2 VERIFICATION OF OPERATION
To verify the operation of the sensor/transmitter unit, make sure that is still responding to gas.
This test should be performed every six (6) months, but for more demanding applications,
verification should be performed on a monthly basis.
6.3 SENSOR REPLACEMENT
Caution:
Turn off the main power supply before attempting the following.
Sensor life is in excess of 10 years. When the sensor needs replacing, reorder the Sensor Part
Number listed in Product Information (section 2.1). The sensor should be replaced under the
following conditions (see FIGURE 7 for sensor replacement procedure):
1. When the sensor element becomes an open circuit, the transmitter outputs a fixed 1 mA
+/- 0.10 mA signal.
2. When the sensor no longer responds to the presence of gas or has an unstable zero
signal.
Note:
Allow 10 minutes for new sensor element to stabilize (burn-in) before recalibration, and
then follow instructions in calibration section 5.2 of this manual.

AMC-350 Sensor/Transmitter
15
FIGURE 7: Sensor replacement procedure.