ENMET Corporation PO Box 979 Ann Arbor, MI 48106-0979 ISA-40M Oxygen Monitor For MRI Scanner Applications For P/N’s 04615-001 04615-002 04615-003 04615-004 80015-102 revised, 08/16/91 MCN-204, 04/16/99 MCN-256, 06/07/01 MCN-270, 12/17/01 04615-101 04615-102 04615-103 04615-104
Table of Contents 1.0 INTRODUCTION........................................................................................................1 1.1 Unpack................................................................................................................................................. 1 1.2 Check Order....................................................................................................................................... 1 1.3 Serial Numbers...........................................
ISA-40M Oxygen Monitor ENMET Corporation 1.0 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.
ENMET Corporation ISA-40M Oxygen Monitor 2.0 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 LED, Red: Visual alarm (steady light). When this LED is on, power to the unit is on and the unit is in high alarm.
ISA-40M Oxygen Monitor ENMET Corporation 3.0 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 Mounting Holes 4 places Transformer Protective Standoff cover 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.
ENMET Corporation ISA-40M Oxygen Monitor 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.
ISA-40M Oxygen Monitor ENMET Corporation ISA-40M Interior View O2 Cell Circuit Board w/cell installed on circuit side Remove Shoring Clip or Spring Bottom View O2 Sensor • Center Pin – Negative • Outer Pin + Positive O2 Cell Circuit Board Figure 3: Oxygen Cell Installation See note below 3.2 Oxygen Cell Installation WARNING: The transducer cell must be installed and the oxygen monitor must be operational prior to using cryogen with the MRI equipment magnet.
ENMET Corporation ISA-40M Oxygen Monitor 3.2.2 Remote Sensor Assembly Wiring See Figure 4 for location of terminal blocks.
ISA-40M Oxygen Monitor ENMET Corporation O2 Cell Port O2 Cell Circuit Board Cover Screws 4 places O2 Cell Screws Do Not over tighten Remote Sensor Assembly Top View Remote Sensor Cover (cut away)Side View Figure 5: Remote Sensor Oxygen Cell Installation (Optional) 3.2.2 Oxygen Cell Installation for Remote Sensors For some ISA-40M systems, single channel systems, and all multichannel systems, remote sensors are connected to the control unit via wiring.
ENMET Corporation ISA-40M Oxygen Monitor 3.3 Relay Outputs Relay contacts can be used to activate other alarm signals or equipment away from the control unit enclosure when there is an alarm condition and when the AC or DC power is interrupted. The contacts supplied are dry, with a rating of 2 Amp continuous, 5 Amp surge. Do not overload the ISA-40M power supply by connecting it through the relay contacts to an inappropriate load. See Wiring Information Tables 3 & 4 and Sections 3.3.1 and 3.3.
ISA-40M Oxygen Monitor ENMET Corporation 3.3.1 Non-Latching Relays There is one non-latching, single pole relay per channel. These relays furnish normally open, normally closed, and common terminals, which are available on TB3 and TB4; refer to the motherboard drawing. These relays are fail-safe; the power off position and the alarm position of the contacts are identical. Contact positions are given for the power off, alarm condition.
ENMET Corporation ISA-40M Oxygen Monitor 4.0 Operation Install and power the unit as previously described in section 3.0 through 3.3.3. The green LED on each channel is an indication that power is on and the unit is not in alarm. The red LED indicates alarm, which is usually set at an oxygen content of 18.0%. The green LED goes out when the red LED goes on. If no LEDs are on, power has been interrupted.
ISA-40M Oxygen Monitor ENMET Corporation 5.0 Maintenance 5.1 Cell Aging The output of the cell decreases with cell usage. The change is very small during the operational life of the cell, 12-14 months, and is compensated by changing the gain to cause the meter reading to be 20.9% in fresh air. Gain reset and rough test (Sections 3.2.3 and 4.1) should be accomplished every 4 – 6 weeks.
ENMET Corporation 1. a) ISA-40M Oxygen Monitor Null adjust: Disconnect the oxygen cell from the circuit by disconnecting leads at TB1 or TB2 as shown below: Channel 1 2 3 4 b) Check the null voltage for the channel.
ISA-40M Oxygen Monitor c) ENMET Corporation Adjust the appropriate meter gain potentiometer, shown below, so the channel's meter reads full scale (26% oxygen on most meters). Adjust this pot. Counterclockwise to increase, clockwise to decrease meter reading. Channel 1 2 3 4 Potentiometer R110 R210 R110 R210 On Circuit Board For channel(s) 1 (and 2) For channels 1 and 2 For channel(s) 3 (and 4) For channels 3 and 4 d) 4. Remove the voltmeter leads from the test points.
ENMET Corporation ISA-40M Oxygen Monitor 6.0 ISA-40M Specifications Control Unit Specifications Power Alarm Sensor Lifetime Electronics Dimensions Weight Enclosure 110 VAC (or 220 VAC if transformer standouts are reconfigured), 50/60 Hz, and/or 12 V DC, 20 watts max. (5 watts per channel) Horn and red LEDs on Control Unit. Approximately 14 months. Warranted for 6 months from date of shipment. Low power, all solid state, utilizing integrated circuits. 12" high x 8" wide x 7" deep 20 lbs.
ISA-40M Oxygen Monitor ENMET Corporation 7.2 Return for Repair ENMET instruments may be returned to the factory or any one of our Field Service Centers for regular repair service or calibration. The ENMET Repair Department and Field Service Centers also perform warranty service work. There is a Repair Return Form on the last page of this manual. This form can be copied or used as needed.
ENMET Corporation ISA-40M Oxygen Monitor 8.0 WARRANTY ENMET warrants new instruments to be free from defects in workmanship and material under normal use for a period of one year from date of shipment from ENMET. The warranty covers both parts and labor excluding instrument calibration and expendable parts such as calibration gas, filters, batteries, etc... Equipment believed to be defective should be returned to ENMET within the warranty period (transportation prepaid) for inspection.
