ENMET EN User Manual
ENMET Corporation
PO Box 979
Ann Arbor, MI 48106-0979
Manual Part Number
80003-133
MCN-339, 10/04/05
EN / SDS
Electrochemical
Sensor/Transmitter
Installation Manual
Table of Contents
INTRODUCTION ................................................................................................................................................................................... 1
1.0 UPON RECEIPT ............................................................................................................................................................................... 1
1.1 U
NPACK
............................................................................................................................................................................................ 1
1.2 C
HECK ORDER
1.3 S
ERIAL NUMBERS
2.0 MOUNTING AND WIRING ............................................................................................................................................................ 2
2.1 I
NSTALLATION OF SENSOR/TRANSMITTER
3.0 INITIAL CALIBRATION ................................................................................................................................................................ 4
4.0 STANDARD RANGES, CALIBRATION GASES, VOLTAGE READINGS AT CALIBRATION POINTS AND
APPROXIMATE TIMES TO SENSOR STABILIZATION ................................................................................................................. 5
5.0 ENMET PART NUMBERS............................................................................................................................................................... 6
5.1 R
EPLACEMENT SENSORS
5.2 C
ALIBRATION GASES
Calibration Gases and Accessories ................................................................................................................................................... 6
6.0 WARRANTY ..................................................................................................................................................................................... 7
APPENDIX A: INTERFERENCE TABLE ........................................................................................................................................... 8
.................................................................................................................................................................................. 1
............................................................................................................................................................................. 1
........................................................................................................................................ 3
................................................................................................................................................................... 6
........................................................................................................................................................................ 6
List of Illustrations
F
IGURE 1: SENSOR/TRANSMITTER, EXTERNAL FRONT VIEW
F
IGURE 1A: SENSOR/TRANSMITTER
F
IGURE 2: SENSOR/TRANSMITTER 4 – 20MA IN
F
IGURE 2A: SENSOR/TRANSMITTER 4 – 20MA IN
F
IGURE 3: CALIBRATION SETUP, 4 – 20MA SENSOR/TRANSMITTER
T
ABLE 1: ELECTROCHEMICAL SENSORS
10015-1105, E
..................................................................................................................................................... 5
XTERNAL FRONT VIEW
NEMA-4 P
NEMA-4 P
...................................................................................................................... 2
................................................................................................ 2
ACKAGE, INTERNAL VIEW
ACKAGE, INTERNAL VIEW
........................................................................................................... 4
.............................................................................. 3
............................................................................ 3
Sensor/Transmitter, Toxic Gas & Oxygen ENMET Corporation
Introduction
The ENMET toxic and oxygen sensor/transmitters (S/T) model EN series are two wire 4-20mA devices. The housing is a
sealed NEMA-4 aluminum enclosure. The sensor/transmitter operates on 15 to 36VDC and can be connected to any control that
utilizes a 4-20mA output. When connecting the sensor/transmitter to a control consult installation instructions and manuals for
that control or contact ENMET or your ENMET distributor.
N
OTE
: All specifications stated in this manual may change without notice.
1.0 Upon Receipt
1.1 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
N
OTE
: It is your responsibility to follow these instructions. If they are not followed, the carrier will not honor
any claims for damage.
This shipment was carefully inspected, verified and properly packaged at our company and delivered to the carrier in good
condition.
When it was picked up by the carrier at ENMET, it legally became your company’s property.
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.
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.
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, 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.
1.3 Serial Numbers
Each sensor/transmitter is serialized. These numbers are on tags on the equipment and are on record in an ENMET database.
1
Sensor/Transmitter, Toxic Gas & Oxygen ENMET Corporation
2.0 Mounting and Wiring
Each sensor/transmitter circuit and sensor are in a NEMA-4 aluminum enclosure, which has a combination liquid and RFI O-ring
in the cover. When used with an appropriate liquid tight conduit fitting, the enclosure is sealed to the environment. The interior
of a typical S/T is shown in Figure 2.
When determining location of S/T here are 3 main factors to consider.
♦ Density of gas to be detected: high for gases lighter than air and low for gases heavier than air
♦ Leak point: determination of the probable source of a leak
♦ In the flow of air in ventilated rooms.
Mount the sensor/transmitter to an appropriate stable vertical surface with the sensor facing downward.
C
AUTION
: Since the sensor/transmitter detects gas only at the sensor location, pay attention to the possible sources of gas, the
density of the gas, locations where the gas may be confined and locations where the gas may damage or injure property or
personnel, when choosing locations of sensor/transmitters.
Mount the sensor/transmitter using the two mounting holes in the corners of the enclosure. For maximum RFI protection the
enclosure should be grounded to earth ground, either by means of the mounting screws, a conductive conduit, or a wire
connected to earth ground.
2.55”
0.68”
4.55”
Figure 1: Sensor/Transmitter, External Front View
2.55”
0.68”
4.55”
Figure 1a: Sensor/Transmitter 10015-1105, External Front View
2
Sensor/Transmitter, Toxic Gas & Oxygen ENMET Corporation
•
•
•
2.1 Installation of Sensor/Transmitter
1. J Remove the cover, and mount the S/T in a location appropriate for the application. Use the enclosure mounting holes as
shown in Figure 2. The sensor faces down. Pay particular attention to the source and density of the target gas in choosing
the S/T location.
2. J The hole in the left side wall of the S/T enclosure is sized to accommodate a liquid tight conduit fitting. Run conduit from
the S/T to the control. If intrinsically safe barriers are supplied, because the S/Ts are in a classified location, follow the
applicable electrical code provisions for intrinsically safe wiring. Run two wires through conduit. If the conduit is
metallic and does not contain other wiring likely to generate interference signals, unshielded insulated wires can be used.
Otherwise, use two wire shielded cable and ground the shield to the S/T enclosure. The S/T enclosure should be grounded
to earth ground for maximum RFI protection.
3. J Connect the plus wire to TB1-1 and the minus wire to TB1-2 on the S/T circuit board, as shown in Figure 2.
C
AUTION
: Before connecting S/T to C
ONTROL
remove the power source to C
ONTROL
. Failure to do so may cause damage to
sensitive components.
4 – 20mA,
12 – 28VDC
Liquid Tight
Conduit
Fitting
NEMA-4 Aluminum Enclosure
shown without cover
Mounting Hole
2 places
TB1
Circuit Board
Red LED
Sensor
Test Points
POTs: Gain and Zero
• Note: No Zero pot in oxygen S/T
Figure 2: Sensor/Transmitter 4 – 20mA in NEMA-4 Package, Internal View
4 – 20mA,
12 – 28VDC
Liquid Tight
Conduit
Fitting
NEMA-4 Aluminum Enclosure
shown without cover
Mounting Hole
2 places
TB1
Circuit Board
Red LED
Sensor
Test Points
POTs: Gain and Zero
Note: No Zero pot in oxygen S/T
Figure 2a: Sensor/Transmitter 4 – 20mA in NEMA-4 Package, Internal View
3
Sensor/Transmitter, Toxic Gas & Oxygen ENMET Corporation
•
Red LED
POT’s: Gain Zero
•
Note: No Zero pot in Oxygen S/T
3.0 Initial Calibration
The S/T is pre-calibrated at the factory before shipment, and initial field calibration should result in only fine-tuning of the
circuit. In all cases allow the S/Ts to stabilize; this may take as much as an hour depending on the type of sensor and the length
of time it has been inactive. The S/T output is monitored with a voltmeter by means of the test points on the S/T circuit board
see figure 2; the transfer function is:
4mA = 100 mv 20ma = 500 mv
tolerance: + or - 5 mv
On Toxic sensor/transmitters the LED also indicates current flow; it is dim at 4mA and bright at 20mA. When the sensor is
stable and is in air uncontaminated by the target gas, adjust zero to
4mA = 100mv with the zero potentiometer, see Figure 2.
If a calibration kit was purchased and field calibration is desired, apply the span gas to the sensor. The regulator of the
calibration adapter screws into the top of the gas cylinder; the cup of the adapter slips into the hub of the sensor/transmitter, see
Figure 3. Allow the gas to flow for the time indicated in Table 1 in Section 4.0 and observe that the reading is stable. Adjust
the gain potentiometer on the S/T board to the appropriate output while monitoring the voltmeter. The voltage readings for
standard ranges are given in Table 1 in Section 4.0.
If the sensor/transmitter has a non-standard range, and/or a non-standard calibration gas is used do a linear interpolation to
determine the voltage reading at the calibration point.
Example: toxic, if the maximum range is 100ppm = 20ma, and a 25ppm gas is used, adjust the gain potentiometer so that the
display reads 25 or the voltmeter reads 200mv.
(25/100)(500-100) + 100 = 200mv
Example: oxygen, the maximum range is 30.0% = 20mA, and a 20.9 gas is used, adjust the gain potentiometer so the display
reads 20.9 or the voltmeter reads 379mv.
Remove the span gas and replace the S/T cover.
Test Points
TB1
Red LED
CALIBRATION
ADAPTER
Figure 3: Calibration Setup, 4 – 20mA Sensor/Transmitter
(20.9/30)(500-100) + 100 = 379mv
Test Points
TB1
CALIBRATION
ADAPTER
Circuit Board
POTs: Gain and Zero
Note: No Zero pot in oxygen S/T
REGULATOR
GAS CYLNDER
4
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