ENMET ISA-RAL-M User Manual

ENMETENMET Corporation

PO Box 979
Ann Arbor, MI 48106-0979

ISA-RAL-M

ISA-RAH-M

Operation and Maintenance

80002-030

04/10/95
MCN 149, 10/31/95
MCN 162, 03/25/97
MCN 164, 04/02/97
MCN 179, 10/06/97
MCN 204, 10/20/98
MCN 205, 01/19/99
MCN 214, 03/16/99
MCN 220, 09/17/99
MCN 241, 09/22/00
MCN-304, 10/17/03

Manual

Table of Contents

1.0 INTRODUCTION............................................................................................................................................................................1

1.1 OPERATION PRINCIPLE.........................................................................................................................................................................1

1.2 ISA-RAH-M HIGH PRESSURE MONITOR..........................................................................................................................................1

1.3 HYDROCARBON FILTER........................................................................................................................................................................1

2.0 UPON RECEIPT.....................................................................................................................................................................................1

3.0 FEATURES, DEFINITION OF PARTS ..........................................................................................................................................2

3.1 ELECTRONICS CONTROL UNIT ............................................................................................................................................................2

3.2 INTERNAL ELECTRONIC CIRCUITRY...................................................................................................................................................3

3.3 SAMPLE HEAD ASSEMBLY...................................................................................................................................................................4

4.0 INSTALLATION....................................................................................................................................................................................5

5.0 INITIAL WARM-UP AND OPERATION......................................................................................................................................7

5.1 QUICK FIELD TESTS..............................................................................................................................................................................8

6.0 CALIBRATION......................................................................................................................................................................................9

7.0 MAINTENANCE...................................................................................................................................................................................10

7.1 ROUTINE MAINTENANCE ...................................................................................................................................................................10

7.2 SENSOR CABLE REPLACEMENT.........................................................................................................................................................10

7.3 HYDROCARBON FILTER REPLACEMENT ..........................................................................................................................................10

7.4 REPLACEMENT PARTS.........................................................................................................................................................................11

8.0 SPECIFICATIONS ..............................................................................................................................................................................12

8.1 TYPICAL CALIBRATIONS .....................................................................................................................................................................12

8.2 OPTIONS AND V ARIATIONS................................................................................................................................................................12

9.0 WARRANTY ..........................................................................................................................................................................................13

9.1REPAIR OF CERTAIN UNITS.................................................................................................................................................................13

List of Illustrations

Figure 1: Electronics Control Unit................................................................................................................................................................2

Figure 2: High Pressure Regulator................................................................................................................................................................2

Figure 3: Utilizing the Relay Contacts.........................................................................................................................................................3

Figure 5: Internal Electronic Circuitry .........................................................................................................................................................3

Figure 4: Sample Head Assembly ................................................................................................................................................................. 4

Figure 6: Connecting to Compressed Air Line ........................................................................................................................................... 6

Figure 7: Calibration Adapter and Gas ........................................................................................................................................................8

ISA-RAL-M, ISA-RAH-M ENMET Corporation

1.01.0 IntroductionIntroduction

Sandblasting, welding, and spray painting are examples of activities that create potentially hazardous environments.
Such environments contain toxic gases, dust and fumes. An air compressor system with hoods or masks supplies clean
breathing air to workers and minimizes the risk of injury or death; however, carbon monoxide (CO) can contaminate
the air in a compressor system. Carbon monoxide contamination can occur either when the intake air itself is
contaminated, or when the compressor breaks down and overheats. Because of this hazard, Federal OSHA regulations
(Sec. 1910.134) require monitoring of CO in compressed air systems. In addition, the Compressed Gas Association
has set up guidelines governing maximum tolerable levels of CO and other contaminants (Spec. G-7.1) to ensure the
health and safety of persons who use respiratory air lines.

The ENMET ISA-RAL-M (See Figure 1) monitors the carbon monoxide in compressed air used for human breathing.
If the CO concentration exceeds any predetermined levels, the ISA-RAL-M will triggers audio-visual alarms and
activates any associated equipment to alert personnel in potential danger.

NOTE: All specifications stated in this manual may change without notice.

1.1 Operation Principle

The ISA-RAL-M is an all-solid state electronic gas-detecting instrument designed to continuously monitor the carbon
monoxide level in compressed air. The sensing element is a gas-sensitive metallic-oxide semiconductor (MOS). A
regulator-humidifier assembly collects and humidifies a small air sample from the respiratory air line and passes it
over the sensor. When the level of CO in the air passing over the sensor increases to preset values, the instrument
alarms with audio (horn) and visual (light) signals.

The ISA-RAL-M operates from single-phase 110 Vac, single-phase 220 Vac and/or 12 Vdc power and is equipped
with relay contacts to provide additional alarm signals.

1.2 ISA-RAH-M High Pressure Monitor

The ISA-RAH-M is designed to monitor breathing air from cylinders at pressures up to 5000 psi. The equipment
consists of an ISA-RAL-M with the addition of a high-pressure regulator at the sample air input as shown in Figure 2.
The high pressure regulator must be plumbed into the high pressure line with an appropriate fitting; the output is
connected to the ISA-RAL-M by means of a quick release pneumatic fitting. The operation of the ISA-RAH-M is
identical with that of the ISA-RAL-M, and calibration is also identical; the high pressure regulator is removed from the
sample input and the calibration procedures given in this manual are employed.

1.3 Hydrocarbon Filter

There are two versions of the ISA-RAL-M:
P/N 04526-001 is supplied with a hydrocarbon filter
P/N 04526-003 is supplied without a hydrocarbon filter

2.0 Upon Receipt2.0 Upon Receipt

1. Unpack and inspect your new ISA-RAL-M for damage, which might have occurred during shipment.

2. Make sure the instrument is calibrated according to your order.

3. Do not use damaged or incorrect equipment. If there is a problem, contact your distributor or ENMET personnel

immediately.

4. Read this manual thoroughly to assure proper handling, operation, and maintenance of your ISA-RAL-M.

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ENMET Corporation ISA-RAL-M, ISA-RAH-M

Alarm Light

Switch Indicator Light
4 holes, .31 Dia.

3.0 Features, Definition of Parts3.0 Features, Definition of Parts

3.1 Electronics Control Unit

Figure 1 shows the control unit which contains the electronics circuitry and controls. Main features are listed below.

Power Light
(Green)

Alarm Light
(Amber)

Alarm Light
(Red)

Audio Alarm Audio alarm (2900 Hz,95 dB at 2 ft.). The audio alarm is on when the unit is in alarm.
Meter

Operation Switch A rotary switch, for OPERATE (normal operation), HORN OFF (disengage audio

Switch Indicator Light
(Red)

Sensor Cable Oiltight cable. Connects the sample head assembly to the control unit

When this light is on, the unit is operating and is not in alarm. When this light is off,
the unit is in alarm OR power to the unit has been interrupted.

Visual alarm (steady light). When this light is on, power to the unit is on and the unit
is in low alarm.

Visual alarm (steady light). When this light is on, power to the unit is on and the unit
is in high alarm.

A carbon monoxide (CO) concentration meter. The scale is marked in parts per
million (ppm) CO. This is a non-linear device. Do not infer exact readings from
unmarked regions of the meter scale.

alarm) or PURGE ON (sensor temperature control).
PURGE ON to clean (purge) sensor surface of adsorbed contaminants (sensor hot).

Indicates OPERATION SWITCH is not in OPERATE position.

(length 8-10 feet). See Caution in section 4.0 Installation step 5.

(Red)

Alarm Light
(Amber)

Power Light
(Green)

Figure 1: Electronics Control Unit

(Red)

Operation Switch

Meter

Audio Alarm

Sensor Cable

Figure 2: High Pressure Regulator

2

ISA-RAL-M, ISA-RAH-M ENMET Corporation

Normally
Common

110 Vac

Manual On/Off

Suggested wiring configuration for Utilizing Relay Contacts

Low Level Set

High Level Set

Meter Adjust

110 / 115

12 VDC

Internal Relay

TB3

TB2

TB1

K1

K2

3.2 Internal Electronic Circuitry

Figure 5 shows the circuit board and terminal blocks housed inside the hinged oiltight control unit. Specific relays and
adjustments are defined:

Internal Relay Contacts Relays can be used to activate an external remote alarm signal when a

hazardous CO level is detected, or when the ac or dc power is interrupted.
These are double-pole relays with terminals normally open, normally closed
and common (see Figure 3 for relay contact hook-up). There is one relay for
each alarm level.

Potentiometers: The unit has five potentiometers. Only 3 are used by the customer. These vary

critical circuit resistances and are essential to calibration procedures. These
potentiometers are described below.

Meter Adjust To adjust and set the meter for appropriate gas response during calibration.
Low Level Set To adjust the trip level of the amber gas alarm light and the audio alarm.
High Level Set To adjust the trip level of the red gas alarm light and the audio alarm.

(manual on/off switch is suggested; user supplied component)

Contact

Closed
Contact

Switch

Horn

Black

White

Power supply Outside

of Control Unit

Non-Latching Relay contacts:

Identified below is the non-powered
(power to unit is off), alarm positions of
the non-latching relay contacts.

Contacts

Terminal Block 2 see Figure 5

Relay 1 High Alarm
Relay 2 Low Alarm

NOTE: N.C.= normally closed

N.O.= normally open

Red Lamp ----

INPUT

Jumper Holder

Green Lamp

N.O.

COM.

Relay 1

Battery

Purge

Amber Lamp

N.C.

COM.

Relay 2

GND

Backup

Sensor

GND

N.O.

Signal

Meter+

N.C.

Heater

Meter–

GND

Potentiometer

Jumper 2

GND

GND

Jumper 3

Jumper 5

RV38

TP1

TP2

RV35

RV32

110 VAC

Jumper 4

Jumper 1

TB4

RV33

110 VAC

Potentiometer

RV34

Potentiometer

GND

OR

210 / 230*
*See Section 4.0

Figure 3: Utilizing the Relay Contacts

Figure 5: Internal Electronic Circuitry

3