ENMET ISA-40M User Manual
ENMETENMET Corporation
PO Box 979
Ann Arbor, MI 48106-0979
ISA-40M Oxygen Monitor
For MRI Scanner Applications
For P/N’s
04615-001 04615-101
04615-002 04615-102
04615-003 04615-103
04615-004 04615-104
80015-102
revised, 08/16/91
MCN-204, 04/16/99
MCN-256, 06/07/01
MCN-270, 12/17/01
Table of Contents
1.0 INTRODUCTION........................................................................................................1
1.1 Unpack.................................................................................................................................................1
1.2 Check Order .......................................................................................................................................1
1.3 Serial Numbers...................................................................................................................................1
2.0 F EATURES..............................................................................................................2
3.0 INSTALLATION ........................................................................................................3
3.1 Control Unit Mounting and Power Hook-up................................................................................3
3.1.1 Converting to 220 Vac Power.............................................................................................4
3.2 Oxygen Cell Installation...................................................................................................................5
3.2.1 Oxygen Cell Installation Inside of Control Unit..............................................................5
3.2.2 Remote Sensor Assembly Wiring.........................................................................................6
3.2.2 Oxygen Cell Installation for Remote Sensors...................................................................7
3.2.3 Oxygen Gain Adjustment......................................................................................................7
3.2.4 Circuit board Removal.........................................................................................................7
3.3 Relay Outputs.....................................................................................................................................8
3.3.1 Non-Latching Relays.............................................................................................................9
3.3.2 Latching Relays......................................................................................................................9
4.0 OPERATION.......................................................................................................... 10
4.1 Rough Test........................................................................................................................................10
4.2 Precautions Regarding the Cell.....................................................................................................10
4.3 Atmospheric Pressure Variations..................................................................................................10
4.4 Temperature Variations .................................................................................................................. 10
5.0 MAINTENANCE...................................................................................................... 11
5.1 Cell Aging.........................................................................................................................................11
5.2 Cell End-of-Life...............................................................................................................................11
5.3 Circuit Alignment............................................................................................................................11
5.4 Circuit Breakers / Fuse...................................................................................................................13
6.0 ISA-40M SPECIFICATIONS ..................................................................................... 14
7.0 SERVICE INFORMATION.......................................................................................... 14
7.1 Replacement Part Numbers...........................................................................................................14
7.2 Return for Repair.............................................................................................................................15
8.0 WARRANTY....................................................................................................... 16
List of Illustrations
FIGURE 1: ISA-40M CONTROL UNIT EXTERIOR.............................................................................2
FIGURE 2: MOUNTING DIMENSIONS..............................................................................................3
TABLE 1: POWER SUPPLY WIRING ..............................................................................................3
FIGURE 3: OXYGEN CELL INSTALLATION......................................................................................5
TABLE 2: REMOTE S ENSOR ASSEMBLY WIRING............................................................................6
FIGURE 4: INTERIOR VIEW OF S ENSOR ASSEMBLY.........................................................................6
FIGURE 5: REMOTE S ENSOR OXYGEN CELL INSTALLATION (OPTIONAL)............................................7
FIGURE 6: UTILIZING THE RELAY CONTACTS.................................................................................8
TABLE 3: NON-LATCHING RELAY WIRING.....................................................................................9
TABLE 4: LATCHING RELAY WIRING............................................................................................9
FIGURE 7: LOCATION OF CIRCUIT BOARDS, T EST POINTS AND POTENTIOMETERS .............................11
ISA-40M Oxygen Monitor ENMET Corporation
1.0 Introduction1.0 Introduction
The ISA-40M system is designed to monitor the oxygen content of atmospheres in the vicinity of MRI (Nuclear
Magnetic Resonance) equipment. Air contains 20.9% oxygen by volume; if oxygen in the air is displaced by a liquid
cryogen (such as nitrogen) leak in MRI equipment, the oxygen deficient atmosphere could become hazardous to
human life. To minimize the effects of magnetic fields generated by MRI equipment, LED's and brass hardware are
used in the ISA-40M.
The ISA-40M system employs galvanic micro-fuel cells as oxygen detection transducers. The output current of each
cell increases or decreases according to the partial pressure of oxygen in the surrounding air, which corresponds to the
oxygen content. The system monitors the oxygen content continuously, and if the oxygen content at any sensor location
drops to the alarm point (usually 18.0% by volume), the instrument provides audio and visual alarms at the control unit.
An audio alarm also occurs at the sensor location. Internal relay contacts can be used to activate additional alarm signals
and/or external equipment. Oxygen content from 16% to 26% by volume is constantly displayed by meters on the
control unit. The ISA-40M system is an alarm device which minimizes the risk of harm or death to personnel by
warning them of a hazardous oxygen deficient atmosphere with enough time for them to take action.
An ISA-40M system consists of a number of identical channels of oxygen deficiency detection. Each circuit cell
combination makes up a separate channel. ISA-40M-2 has two identical circuits with related oxygen cells; likewise,
an ISA-40M-4 has four channels. If the cell is enclosed in a remote sensor, each cell can be located in a separate area
up to 1000 feet from the instrument enclosure. The cells are connected to the control unit electrically by wire or cable.
Each plug-in circuit board contains the circuitry for two channels. ISA-40M instruments described in this manual can
contain up to 4 channels. This particular manual is for the ISA-40M-1 through the ISA-40M-4 .
NOTE: All specifications stated in this manual may change without notice.
1.1 Unpack
Unpack the ISA-40M and examine it for shipping damage. If such damage is observed, notify both ENMET customer service
personnel and the commercial carrier involved immediately.
Regarding Damaged Shipments
NOTE: It is your responsibility to follow these instructions. If they are not followed, the carrier will
not honor any claims for damage.
q This shipment was carefully inspected, verified and properly packaged at our company and delivered to the carrier in good condition.
q When it was picked up by the carrier at ENMET, it legally became your company’s property.
q If your shipment arrives damaged:
• Keep the items, packing material, and carton “As Is.” Within 5 days of receipt, notify the carrier’s local office and request
immediate inspection of the carton and the contents.
• After the inspection and after you have received written acknowledgment of the damage from the carrier, contact ENMET Customer
Service for return authorization and further instructions. Have your Purchase Order and Sales Order numbers available.
q ENMET either repairs or replaces damaged equipment and invoices the carrier to the extent of the liability coverage, usually
$100.00. Repair or replacement charges above that value are your company’s responsibility.
q The shipping company may offer optional insurance coverage. ENMET only insures shipments with the shipping company when
asked to do so in writing by our customer. If you need your shipments insured, please forward a written request to ENMET
Customer Service.
Regarding Shortages
If there are any shortages or questions regarding this shipment, please notify ENMET Customer Service within 5 days of receipt at
the following address:
ENMET Corporation
680 Fairfield Court
Ann Arbor, MI 48108
734-761-1270 734-761-3220 Fax
1.2 Check Order
Check, the contents of the shipment against the purchase order. Verify that the ISA-40M is received as ordered. If there are
accessories on the order, verify that they are present. Check the contents of calibration kits. Notify ENMET customer service
personnel of any discrepancy immediately.
1.3 Serial Numbers
Each ISA-40M is serialized. These numbers are on tags on the equipment and are on record in an ENMET database.
1
ENMET Corporation ISA-40M Oxygen Monitor
Relay
O2
O2
O2
O2
Audio Alarm
Relay Reset
Channel 1
Channel 1
Channel 1
Channel 1 Gain
Cover Screws
2.0 Features2.0 Features
See figure 1 for location of features
Feature Description
Meter A Oxygen (O2) concentration meter. The scale is marked in percent by volume O2.
Audio Alarm(Horn) Audio alarm (2900 Hz,95 dB at 2 ft.). The audio alarm is on when the unit is in alarm.
Gain Potentiometer
Visual Alarms
Relay Reset Button
LED, Red: Visual alarm (steady light). When this LED is on, power to the unit is on and
the unit is in high alarm.
LED, Green: When this is on, the unit is operating and is not in alarm. When this LED is
off, the unit is in alarm OR power to the unit has been interrupted.
Potentiometer
Alarm LED (red)
Power LED (green)
Meter
4 places
1
(Horn)
Gain
2
Gain
3
Button
Gain
Reset
4
Gain
Figure 1: ISA-40M Control Unit Exterior
2
ISA-40M Oxygen Monitor ENMET Corporation
Mounting Holes
Transformer
Protective
Standoff cover
3.0 Installation3.0 Installation
WARNING: This equipment is not for use in hazardous combustible atmospheres as defined by the national
electrical code. Use in such atmospheres may result in property damage, injury or death
4 places
Fuse
TB3
TB5
Circuit Breakers
Figure 2: Mounting Dimensions
3.1 Control Unit Mounting and Power Hook-up
Use an appropriate fitting for conduit when supplying power to the unit.
1. Choose a suitable location for mounting the electronics control unit. See Figure 2 for mounting dimensions.
NOTE: All dimensions are given in inches.
2. Apply 110 VAC and/or 12 V DC power to the appropriate terminals on TB5 and TB3. Refer to the Wiring
Information table. Both 110 VAC and 12 V DC power can be applied together; the 12 VDC is standby power
source; DC current will flow only when the AC power is interrupted.
Table 1: Power Supply Wiring
Power supply ISA-40M Control Unit connection
110 VAC HOT TB5 HOT
110 VAC NEUTRAL TB5 NEUT
AC ground TB5 GND
12 VDC TB3-3 + V DC
DC ground TB3-1 or TB3-2
3
ENMET Corporation ISA-40M Oxygen Monitor
Standoffs
Standoffs
Protective
3.1.1 Converting to 220 Vac Power
The input of the transformer must be changed in order to accommodate 220 VAC power. This is accomplished by
changing the wiring between four standoffs located under a protective cover next to the transformer, shown in Figure 1.
The wiring configurations and the power supply schematics are shown in Figure 5.
To change power supply wiring of transformer form 110 VAC to 220 VAC, resolder the transformer standoff leads to the
appropriate configuration shown below. The materials required for this are a flathead screwdriver a soldering iron, 18
gauge (or larger) insulated wire and 60% tin/40% lead resin sore solder.
CAUTION: This procedure should be performed only by personnel with electrical repair experience.
1. Disconnect power from control unit.
2. Remove instrument circuit board to access transformer standoffs on motherboard.
3. Unscrew the cover-retaining screw and rotate protective standoff cover until standoffs are exposed.
4. Unsolder one lead at a time and then resolder to desired configuration (shown below).
5. Wipe up and remove excess solder.
6. Rotate protective cover over standoffs and tighten screws and replace circuit board.
110 VAC Wiring 220 VAC Wiring
Standoff Cover
(1,2,3,4)
2
4
1
Transformer
3
Standoff Cover
Protective
(1,2,3,4)
1
2
3
4
110 VAC Schematic 220 VAC Schematic
Transformer
4
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