ENMETENMET Corporation
PO Box 979
Ann Arbor, MI 48106-0979
Catalytic & MOS
Sensor/Transmitter Installation
Manual
80003-029
MCN-182, 02/11/98
MCN-204, 02/29/00
MCN-230, 02/29/00
MCN-234, 04/25/00
MCN-240, 10/30/00
MCN-247, 11/21/00
MCN-253, 04/05/01
MCN-265, 12/13/01
MCN-290, 11/20/02
Table of Contents
1.0 INTRODUCTION............................................................................................................................................ 1
1.0.1 Unpack............................................................................................................................................................................................1
1.0.2 Check Order...................................................................................................................................................................................1
1.0.3 Serial Numbers..............................................................................................................................................................................1
1.2 Features of Sensor / Transmitter .........................................................................................................................................................2
1.2.1 Magnetic Switches and Potentiometers....................................................................................................................................2
2.0 CATALYTIC COMBUSTIBLE GAS S ENSOR/TRANSMITTER INSTALLATION ...............................................................3
2.1 Installation..............................................................................................................................................................................................3
2.1.1 Mounting........................................................................................................................................................................................3
2.1.2 Wiring.............................................................................................................................................................................................4
2.2 Calibration..............................................................................................................................................................................................4
2.3 Standard Range and Alarm LED ........................................................................................................................................................ 5
3.0 MOS COMBUSTIBLE AND TOXIC VAPOR SENSOR/T RANSMITTER INSTALLATION....................................................6
3.1 Installation..............................................................................................................................................................................................6
3.1.1 Mounting........................................................................................................................................................................................6
3.1.2 Wiring.............................................................................................................................................................................................7
3.2 Initial Calibration .................................................................................................................................................................................. 8
3.3 Purge.......................................................................................................................................................................................................8
3.4 Span Adjustment...................................................................................................................................................................................8
3.5 Calibration..............................................................................................................................................................................................8
4.0 WARRANTY............................................................................................................................................. 9
ADDENDUM: AMMONIA CALIBRATION.................................................................................................................10
List of Illustrations
Figure 1a: Features of Sensor/Transmitter...................................................................................................................................................2
Figure 1: Mounting Dimensions of Catalytic Combustible Gas Sensor/Transmitter...........................................................................3
Figure 2: Terminal Strip Positions for Catalytic Combustible Gas Sensor/Transmitter......................................................................4
Figure 3: Catalytic Combustible Gas Sensor/Transmitter.........................................................................................................................5
Figure 4: Mounting Dimensions of MOS Sensor/Transmitter.................................................................................................................6
Figure 5: Terminal Strip Positions for MOS Sensor/Transmitter............................................................................................................7
Figure 6: Gas cylinder and Typical Calibration Adapter..........................................................................................................................8
Figure 7: Calibration Adapter with Humidifier..........................................................................................................................................8
Reference information:
NOTE: [important information about use of instrument – if not followed may have to redo some steps.]
CAUTION: [affects equipment – if not followed may cause damage to instrument, sensor etc…]
WARNING: [affects personnel safety – if not followed may cause bodily injury or death.]
Catalytic & MOS S/T ENMET Corporation
1.0 Introduction1.0 Introduction
The ENMET catalytic and MOS sensor/transmitters (S/T) are, three or four wire 4-20 ma S/T for the detection of
combustible and toxic gas. They are meant to be used in conjunction with an appropriate power supply and controller.
Each S/T is in an enclosure rated for use in a Class I, Div. 1, Groups B, C, D, classified area.
NOTE: All specifications stated in this manual may change without notice.
1.0.1 Unpack
Unpack the sensor/transmitter (S/T) 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
1.0.2 Check Order
Check, the contents of the shipment against the purchase order. Verify that the S/T is received as ordered. Each S/T
is labeled with its target gas. If there are accessories on the order, ascertain that they are present. Check the contents
of calibration kits. Notify ENMET customer service personnel of any discrepancy immediately.
1.0.3 Serial Numbers
Each S/T is serialized. These numbers are on tags on the equipment and are on record in an ENMET database.
1
ENMET Corporation Catalytic S/T
ZERO
Increase Span
Decrease Zero
Decrease Span
Increase Zero
Label: Alarm Point
1.2 Features of Sensor / Transmitter
1.2.1 Magnetic Switches and Potentiometers
Magnetic switches control the span and purge potentiometer; a magnetic field pulse is applied by momentarily putting
the end of the magnet in proximity to the switch and then removing it. Since the magnetic field penetrates the
window, the enclosure cover is not removed in order to perform calibration.
The switch locations are indicated by “+ and –”. “+” increases the value and “–” decreases it. Incremental changes in
span can be obtained by momentarily putting the end of the magnet in proximity to the switch and then removing it; when
the magnet is held in proximity to the switch and not removed, the switch indexes continuously to the end of its range.
See figure 1a, Locations of Typical Indicators and Controls on Display Plate for the locations of the following magnetic switches
+ Span increase For increasing span.
– Span decrease For decreasing span.
P Purge When the purge option is present. For cleaning of a contaminated sensor, the
using Magnet
using Magnet
Label: Range
Locations of Typical Indicators
and Controls on Display Plate Potentiometer Locations
NOTE: Do not adjust these unless calibration
gas is applied to the sensor.
heater voltage is increased up to 20% by activating the purge switch for a short
time. There is an associated yellow LED, indicating when purge is activated.
and Gas
Display
using Magnet
using Magnet
Span
Potentiometer
Alarm
Potentiometer
Heater Potentiometer
CAUTION: This POT is factory set;
resetting may damage sensor
Potentiometer
See figure 1a, Potentiometer Locations for the locations of the following manual potentiometers on the S/T circuit board:
Figure 1a: Features of Sensor/Transmitter
RV0 Zero For zeroing of the display in clean air. Refer to calibration procedure, section 3.2 use this
potentiometer before applying calibration gas.
RV1 Heater For adjusting the heater voltage of MOS sensors. Do not reset this potentiometer unless
advised by ENMET personnel.
RV2 Alarm For setting the point at which the red LED on the S/T face plate is illuminated. Use the
zero potentiometer to set the display at the alarm point value desired, then use this
potentiometer to set the LED to turn on at this point. Then return the display to zero. The
factory default setting is the high alarm set point.
RV3 Span For manually setting the span. Do not reset this potentiometer unless advised by ENMET
personnel.
CAUTION: Area must be declassified before removing cover to access these potentiometers.
2
Catalytic S/T ENMET Corporation
Mounting Holes
Sensor/Transmitter
Sensor/Transmitter
Conduit fitting
Approx.
2.0 Catalytic Combustible Gas Sensor/Transmitter Installation2.0 Catalytic Combustible Gas Sensor/Transmitter Installation
The ENMET catalytic combustible gas sensor/transmitter (S/T) is a three or four wire 4-20 mA S/T for the detection
of combustible gas. The S/T is meant to be used in conjunction with an appropriate power supply and controller. The
S/T is in an enclosure rated for use in a Class I, Div. 1, Groups B, C, D, classified area.
2.1 Installation
CAUTION: Area must be declassified during installation.
2.1.1 Mounting
Mount the enclosure, using the two mounting holes provided see figure 1. Pay particular attention to the source and
density of the gas being detected when choosing the location.
CAUTION: Before connecting S/T to controller remove the power source to controller. Failure to do so may cause
damage to sensitive components.
Typically: ½″″ NPT female
2 places, 0.313 ″″
12″
TOP VIEW
Sensor
Enclosure Top View
Enclosure Side View
5″
Sensor
SIDE VIEW
Figure 1: Mounting Dimensions of Catalytic Combustible Gas Sensor/Transmitter
3
ENMET Corporation Catalytic S/T
Terminal Strip
Sensor 03070-003
Sensor 03070-001
Sensor 03070-001
2.1.2 Wiring
Run conduit and 16 AWG wires to the enclosure from the power supply and controller. Since combustible gas may be
present, the S/T may be installed in a Class I Division 1 classified area as defined by the National Electrical Code, and
wiring must meet the provisions of that Code. All wires must pass through the seal fitting provided, and the fitting
must be potted after wiring is complete.
Open the enclosure, and remove the display from the circuit board by pulling it straight out. Release the two circuit
board retaining screws and remove the circuit board, exposing the terminal strip in the bottom of the enclosure. Do not
disconnect the circuit board wiring.
Connect the wires from the power supply and controller to the terminal strip. See figure 2 locations are as follows:
Internal View of S/T Terminal Strip
CONTROLLER WIRING
Position Function
1. 4 - 20 mA loop +
2. Loop ground
3. Power supply ground
4. +15 to 36 VDC power
Internal Threads
External Threads
External Threads
SENSOR WIRING
Position Function Wire Color for Sensor
(external threads) 03070-001 (internal threads)
5 Compensator Red or Black Red
6 Output Yellow or Red White
7 Detector Blue or White Black
8 Not Used
Wire Color for Sensor
03070-003
Figure 2: Terminal Strip Positions for Catalytic Combustible Gas Sensor/Transmitter
When using the S/T as a three wire device, use either ground as both power supply and loop ground.
After connecting the wires, replace the circuit board and the display, assure the LEDs are in the lenses. Replace the
enclosure cover.
See the instruction manual of the Controller being used with this S/T for the connection locations for these wires.
2.2 Calibration
Wait 24 hours after initially supplying power to the sensor/transmitter(S/T) before initial calibration. The S/T has been
precalibrated at the factory, and initial field calibration should result in only fine tuning to circuit, as well as a way to
check that installation is successful. It is not necessary to open the enclosure to make adjustment; the span and zero
potentiometers are operated with magnets from outside the enclosure.
CAUTION: Do not open in classified area.
Do Not Adjust The Span Potentiometer Without Calibration Gas Applied to The Sensor ; if this is done, the S/T is
rendered uncalibrated and incorrect. Magnetic switches control the span and zero potentiometers. The switch
locations are indicated by “+ and – Span” and “+ and – Zero” on the display panel per Figure 3; “+” increases the
value and “–” decreases it. Incremental changes in span and zero can be obtained by momentarily putting the end of
the magnet in proximity to the switch and then removing it; when the magnet is held in proximity to the switch and not
removed, the switch indexes continuously to the end of its range.
4
Catalytic S/T ENMET Corporation
Red ‘Alarm’ LED
Span +
Zero +
Zero ––Span ––
Calibration Cover 03620-015
use with sensor 03070-003
Calibration Cover 03620-012
use with sensor 03070-001
Fitting to
calibration cover
Regulator
Gas Cylinder
Figure 3: Catalytic Combustible Gas Sensor/Transmitter
1. Apply the calibration gas associated with the S/T to the sensor. See to Figure 3.
2. Allow the gas to flow 3 minutes.
3. Use the magnet to adjust the span potentiometer up or down, until the display reads the calibration gas value.
4. Remove the calibration gas.
5. In clean air, adjust the zero point if necessary, using the magnet to adjust the zero potentiometer.
6. If the zero point adjustment is large, greater than 10% LEL, apply the calibration gas again, and make a second
span adjustment.
7. Calibration is complete.
2.3 Standard Range and Alarm LED
The standard range is 0-100 %LEL of the combustible gas being monitored, with 100%LEL producing 20mA in the
loop. The red alarm LED is set to turn on at the high alarm level of the gas. The high alarm level and particular gas
are indicated above the LED.
5
ENMET Corporation MOS S/T
12”
5”
3.0 MOS 3.0 MOS Combustible and Toxic Vapor Sensor/Transmitter InstallationCombustible and Toxic Vapor Sensor/Transmitter Installation
3.1 Installation
CAUTION: Area must be declassified during installation.
3.1.1 Mounting
Mount the enclosure, using the two mounting holes provided see figure 4. Pay particular attention to the source and
density of the gas being detected when choosing the location.
CAUTION: Before connecting S/T to controller remove the power source to controller. Failure to do so may cause
damage to sensitive components.
Conduit Fitting
Typically: ½″″ NPT female
Mounting Holes
2 places
Sensor
Sensor
Approx.
5.25”
3.875”
4.875”
TOP VIEW
Sensor/Transmitter
Enclosure Top View
Sensor/Transmitter
Enclosure Side View
SIDE VIEW
Figure 4: Mounting Dimensions of MOS Sensor/Transmitter
6
MOS S/T ENMET Corporation
Sensor Markings
3.1.2 Wiring
Run conduit and 16 AWG wires to the enclosure from the power supply and controller. Since combustible gas may be
present, the S/T may be installed in a Class I Division 1 classified area as defined by the National Electrical Code, and
wiring must meet the provisions of that Code. All wires must pass through the seal fitting provided, and the fitting
must be potted after wiring is complete.
Open the enclosure, and remove the display from the circuit board by pulling it straight out. Release the two circuit
board retaining screws and remove the circuit board, exposing the terminal strip in the bottom of the enclosure. Do not
disconnect the circuit board wiring.
Connect the wires from the power supply and controller to the terminal strip TB1.
See figure 5 locations are as follows:
CONTROLLER WIRING
S/T Internal View with Circuit Board Removed
Position Function
TB1-1 4 - 20 mA loop +
TB1-2 Loop ground
TB1-3 Power supply ground
TB1-4 +15 to 36 VDC power
1
2
3
4
5
6
7
8
Terminal Strip TB1
812 is stamped 12
813 is stamped 13
For instruments serial # 777 and above
812 / 813 / 814 SENSOR WIRING
Position Function Wire Color
TB1-5 Heater (Brown)
TB1-6 Signal (Blue)
TB1-7 Ground (Orange)
TB1-8 Not Used
For instruments serial # 776 and below
812 SENSOR WIRING
Position Function Wire Color
TB1-5 Heater (Orange)
TB1-6 Signal (Blue)
TB1-7 Ground (Brown)
TB1-8 Not Used
813 / 814 SENSOR W IRING
Position Function Wire Color
TB1-5 Ground (Brown)
TB1-6 Signal (Blue)
TB1-7 Heater (Orange)
TB1-8 Not Used
814 is stamped 19
Figure 5: Terminal Strip Positions for MOS Sensor/Transmitter
See the instruction manual of the Controller being used with this S/T for the connection locations for these wires.
When using the S/T as a three wire device, use either ground as both power supply and loop ground.
After connecting the wires, replace the circuit board and the display; assure the LEDs are in the lenses. Replace
enclosure cover.
7
ENMET Corporation MOS S/T
Sensor/Transmitter
3.2 Initial Calibration
The S/T has been precalibrated at the factory before shipment, and initial field calibration should result in only finetuning of the circuit. Wait at least 24 hours after initially supplying power to the S/T before initial calibration. If
purge option is available, see purge section 3.3.
It is important to zero the S/T before applying the calibration gas. If the display is not reading at or very close to zero,
apply clean air to the sensor.
If sensor does not zero:
§ Declassify the area before opening the enclosure.
§ Apply clean air (20.9% O2 78.1% N2) to the sensor and adjust the zero manual potentiometer to provide a reading
of zero on the display. See the circuit board diagram figure 1a for the location of this potentiometer.
§ Then close the enclosure.
NOTE: These potentiometers are accessible without removing the display plate.
3.3 Purge
When this option is present, activate before calibration. While activating the purge switch the yellow LED is lit to
indicate the purge switch is active. A sensor needs only 10 to 30 seconds of purge. After removal of magnet the
switch and heater voltage will return to their normal state. After purge, the sensor needs to stabilize for 30 minutes
before applying calibration gas.
3.4 Span Adjustment
Do Not Adjust the Span Potentiometer Without Calibration Gas Applied To The Sensor ; if this is done, the S/T is
rendered uncalibrated and incorrect.
§ If your calibration kit is supplied with a humidifier, fill the humidifier bowl half way with clean tap water. See figure 7
§ Attach the calibration adapter to the cylinder of gas associated with the S/T. See figure 6
§ Attach the calibration cover over the sensor. See figure 6
§ Apply the calibration gas to the sensor typically 3 minutes.
§ Use the magnet to adjust the span potentiometer up or down, until the display reads the calibration gas value.
§ Remove the calibration gas.
Sensor
Calibration
Cover
Calibration
Adapter
Gas Cylinder
Figure 6: Gas cylinder and Typical Calibration Adapter
Humidifier Bowl
Figure 7: Calibration Adapter with Humidifier
3.5 Calibration
Subsequent calibrations are performed without opening the enclosure by applying calibration gas and using the magnet
to set the span as described above.
8
Catalytic & MOS S/T ENMET Corporation
4.0 WARRANTY4.0 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. If the evaluation by
ENMET confirms that the product is defective, it will be repaired or replaced at no charge, within the stated
limitations, and returned prepaid to any location in the United States by the most economical means, e.g. Surface
UPS/RPS. If an expedient means of transportation is requested during the warranty period, the customer is responsible
for the difference between the most economical means and the expedient mode. ENMET shall not be liable for any
loss or damage caused by the improper use of the product. The purchaser indemnifies and saves harmless the
company with respect to any loss or damages that may arise through the use by the purchaser or others of this
equipment.
This warranty is expressly given in lieu of all other warranties, either expressed or implied, including that of
merchantability, and all other obligations or liabilities of ENMET which may arise in connection with this equipment.
ENMET neither assumes nor authorizes any representative or other person to assume for it any obligation or liability
other than that which is set forth herein.
NOTE: When returning an instrument to the factory for service:
§ Be sure to include paperwork.
§ A purchase order, return address and telephone number will assist in the expedient repair and return of your unit.
§ Include any specific instructions.
§ For warranty service, include date of purchase
§ If you require an estimate, please contact ENMET Corporation.
There are Return for Repair Instructions and Form on the last pages of this manual. This Form can be copied or used
as needed.
9
ENMET Corporation Catalytic &MOS S/T
Addendum: Ammonia CalibrationAddendum: Ammonia Calibration
Calibration Procedure for EX-5000 MOS Ammonia
The EX-5000 MOS Ammonia sensor requires special calibration techniques that are not common with other gases.
All MOS sensors require at least 15% RH for proper operation. RH of 50% or greater is ideal for MOS sensor
calibration. The common technique for humidifying dry gas from a cylinder is to bubble it through a humidifier
assembly. However, ammonia is readily absorbed in water.
ENMET Corporation has supplied a special calibration adapter for ammonia that allows the humidifier bowl to be 1/3
full of water, but not bubble the gas sample. Instead the gas sample is passed over the water. It is still able to pick up
enough humidity to properly calibrate the sensor, but not enough to lose all of the ammonia calibration gas.
For up to 0-500 ppm range Ammonia transmitters, the proper calibration gas cylinder is approximate 300 ppm NH3 in
air. While flowing the 300 ppm ammonia through the calibration adapter humidifier assembly, approximately 200
ppm is the actual concentration going to the sensor , the difference being absorbed by the water surface. See the
cylinder for the humidified output.
Open the valve on the calibration adapter regulator, and attach the calibration cup to the sensor. Verify that the gas
sample is passing over the water by looking for gentle ripples on the water surface and not bubbling. Flow rate is
preset by the regulator and needs no adjustment. Apply the calibration gas for four minutes. At the end of four
minutes, use the magnet to adjust the – or + buttons and make the display read the humidified output +/- 20 ppm.
10
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