Detcon 1000-H2S User Manual

Detcon Model 1000

H2S Process Analyzer - Electrochemical Sensor

PARTNO.

MODELNO.

SERIALNO.

INPUTVOLTAGE

FREQUENCY

CURRENTLOAD

AREACLASSIFICATION

3200A-1Research ForestDr.

TheWoodlands,TX 77381

www.detcon.com

detconinc.

SAMPLE

FLOW

AIR AIR

INLET

AIR

FLOW

SAMPLE

SAMPLE

SAMPLE

INLET

OUTLET

SAMPLEPRESSURE
10PSIG (CONSTANT)

INLET

Operator’s Installation and Instruction Manual

Detcon Model 1000 Series H2S Analyzer consists of two major assemblies:

1. The Model 1000 Series gas sample-conditioning assembly.

2. The Model DM-624 H2S gas sensor (using Alcohol Free - Electrochemical Sensor or
Hi-Range Electrochemical Sensor)

DETCON, Inc.

4055 Technology Forest Blvd.,

The Woodlands, Texas 77381

Ph.281.367.4100 / Fax [phone]

www.detcon.com

June 6, 2012• Document #2945• Revision 2.8

This page left intentionally blank

Model 1000 H2S Echem

Model 1000 H2S Echem Instruction Manual ii

Model 1000 H2S Echem

Table of Contents

1. Introduction........................................................................................................................................1

1.1 DM-624 Sensor ...............................................................................................................................1

1.2 Electrochemical Sensor....................................................................................................................2

1.3 Microprocessor Control Circuit........................................................................................................2

1.4 Base Connector Board.....................................................................................................................3

1.5 Interference Data.............................................................................................................................4

1.6 Explosion Proof Enclosures.............................................................................................................4

2. Specifications ......................................................................................................................................5

3. Installation..........................................................................................................................................6

3.1 Mounting.........................................................................................................................................6

3.2 Gas Connections and Sampling System Notes..................................................................................6

3.3 Electrical Connections.....................................................................................................................9

3.4 Relays and RS-485 Setup...............................................................................................................10

4. Start Up.............................................................................................................................................12

5. Operating Software........................................................................................................................... 13

5.1 Programming Magnet Operating Instructions................................................................................. 13

5.2 Operating Software........................................................................................................................13

5.2.1 Normal Operation..................................................................................................................13

5.2.2 Calibration Mode...................................................................................................................14

5.2.3 Program Mode....................................................................................................................... 14

5.2.4 Software Flow Chart.............................................................................................................. 16

6. Calibration and Maintenance........................................................................................................... 16

6.1.1 Zero Calibration....................................................................................................................17

6.1.2 Span Calibration....................................................................................................................17

7. Programming Alarms....................................................................................................................... 19

7.1 Alarm Reset...................................................................................................................................19

7.2 Other Alarm Functions ..................................................................................................................19

8. Programming Features..................................................................................................................... 19

9. RS-485 Protocol ................................................................................................................................20

10. Display Contrast Adjustment...........................................................................................................22

11. Low Flow Fault Options...................................................................................................................22

12. Sensor Replacement..........................................................................................................................23

13. Troubleshooting................................................................................................................................23

14. Spare Parts........................................................................................................................................24

15. Warranty........................................................................................................................................... 26

16. Flow Diagrams.................................................................................................................................. 27

17. Wiring Diagram................................................................................................................................ 29

Appendix C .................................................................................................................................................30

Revision Log ............................................................................................................................................30

Model 1000 H2S Echem Instruction Manual iii

Model 1000 H2S Echem

Table of Figures

Figure 1 DM-624 Sensor................................................................................................................................ 1

Figure 2 Construction of Electrochemical Sensor............................................................................................ 2

Figure 3 Functional Block Diagram................................................................................................................ 3

Figure 4 DM-624 Control Circuit ................................................................................................................... 3

Figure 5 Connector Board Terminals.............................................................................................................. 3

Figure 6 Explosion proof enclosures............................................................................................................... 4

Figure 7 Unit Dimensions............................................................................................................................... 6

Figure 8 Port Identification............................................................................................................................. 7

Figure 9 Optional Bubbler Bottle.................................................................................................................... 8

Figure 10 Installation Wiring Connections...................................................................................................... 9

Figure 11 Alarm Jumpers ..............................................................................................................................10

Figure 12 RS-485 Dip Switches.....................................................................................................................11

Figure 13 Programming Magnet ....................................................................................................................13

Figure 14 DM-624 Software Flow Chart........................................................................................................16

Figure 15 Analyzer Parts Identification..........................................................................................................24

Figure 16 DM-624 Replacement Parts...........................................................................................................25

Figure 17 Unit Flow Diagram........................................................................................................................27

Figure 18 Pump Box Flow Diagram ..............................................................................................................28

Figure 19 Wiring Diagram.............................................................................................................................29

List of Tables

Table 1 Hexadecimal Conversion ..................................................................................................................11

Table 2 Sample Flow Rate.............................................................................................................................12

Table 3 Sample Flow Rate.............................................................................................................................17

Shipping Address: 4055 Technology Forest Blvd., The Woodlands Texas 77381

Phone: [phone] • Fax: [phone] • www.detcon.com • [e-mail]

Model 1000 H2S Echem Instruction Manual iv

Mailing Address: P.O. Box 8067, The Woodlands Texas 77387-8067

Model 1000 H2S Echem

1. Introduction

The Detcon Model 1000 Series H2S Process Analyzer is a 110/220VAC or 24VDC powered analyzer that
provides a select gas sample mixture to an on-board DM-624 H2S gas sensor assembly. The range of gas
analysis can span from 0-10ppm up to 0-5% (see Table 2 Sample Flow Rate). The range of analysis is
determined at time of order.

The NEMA 7X rating is achieved by housing all electronic components in suitable NEMA 7X enclosures.
When located outdoors, the H2S Process Analyzer package should be appropriately covered from direct
weather exposure. The Model 1000 Series H2S Process Analyzer can optionally be ordered with a full NEMA
4 enclosure.

The “Power Supply” explosion proof enclosure on the upper right side of the unit houses a 24VDC power
supply, a 24V DC-DC Converter, and a terminal PCB labeled for all input and output field wiring. The
“Pump/Flow” explosion proof enclosure located on the upper left houses an air dilution pump, an activated
carbon scrubber, and optional air flow fault and sample flow fault alarm PCB’s.

The analyzer requires a constant, liquid-free, 10±2psig sample pressure, which is provided by the customer or
may be supplied by Detcon as a separate gas sample handling system.

The on-board gas sample conditioning system includes a stainless steel pressure gauge (0-30psig), and a Genie
membrane filter to provide the analyzer with absolute condensate liquid protection. On the bypass port of the
Genie membrane filter, a 15 psig over-pressure relief valve and flow control valve are also provided. The flow
control valve can be used as a continuous sample bypass and liquid exhaust vent. A dedicated air and sample
mixture is maintained via 2 control valves and 2 rotameters. The Sample is then delivered to the Model DM­624 H2S gas sensor for analysis. An optional on-board span gas cylinder is provided for span calibration, and
a selectable 3-way valve is provided for manually switching between sample monitoring and span calibrations.
An optional Acetic Acid Bubbler apparatus is available to scrub the gas sample when it contains high
concentrations of VOC’s as found in some injection spray H2S scavenger chemistries. An optional live heat
tracing feature may be used to prevent condensation after the Genie Membrane Filter.

®

1.1 DM-624 Sensor

Figure 1 DM-624 Sensor

Model 1000 H2S Echem Instruction Manual Rev. 2.8 Page 1 of 30

Model 1000 H2S Echem

NOTE:

This particular sensor cell is unique in that it has no cross

-

sensitivity to alcohol vapors

Detcon MicroSafe™ Model DM-624, toxic sensors are non-intrusive “Smart” sensors designed to detect and
monitor for H2S gas in the ppm range. A primary feature of the sensor is its method of automatic calibration,
which guides the user through each step via instructions displayed on the backlit LCD. The sensor features
field adjustable, fully programmable alarms and provides relays for two alarms plus fault as standard. The
sensor comes with two different outputs: analog 4-20mA, and serial RS-485. These outputs allow for greater
flexibility in system integration and installation. The microprocessor-supervised electronics are packaged as a
plug-in module that mates to a standard connector board. Both are housed in an explosion proof condulet that
includes a glass lens window that allows for the display of sensor readings as well as access to the sensor’s
menu driven features via a hand-held programming magnet.

1.2 Electrochemical Sensor

The sensor is an electrochemical cell. Each cell consists of three electrodes embedded in an electrolyte
solution all housed beneath a diffusion membrane. Sensitivity to specific target gases is achieved by varying
composition of any combination of the sensor components. Good specificity is achieved in each sensor type.
The cell is diffusion limited via small capillary barriers resulting in long service life of up to 3 or more years
depending on the application.

and thus is a good choice for measuring H2S in natural gas pipelines.

Figure 2 Construction of Electrochemical Sensor

DM-624 Electrochemical Sensor Principle of Operation

Method of detection is by an electrochemical reaction at the surface of an electrode called the sensing
electrode. Air and gas diffuse through the stainless steel filter and the capillary diffusion barrier. The
controlling circuit maintains a small external operating voltage between the sensing and counter electrodes of
the proper bias and magnitude so that no current flows to or from the reference electrode while its potential is
maintained at the correct fixed voltage — usually ground. The electrochemical reaction creates a change in
current flow from the counter electrode to the sensing electrode. This change in current is proportional to the
gas concentration and is reversible. The quick response of the sensor results in continuous monitoring of
sample gas conditions.

1.3 Microprocessor Control Circuit

The control circuit is microprocessor based, and is packaged as a plug-in field replaceable module, facilitating
easy replacement and minimum down time. Circuit functions include a basic sensor pre-amplifier, on-board
power supplies, microprocessor, back lit alpha numeric display, alarm status LED indicators, magnetic
programming switches, an RS-485 communication port, and a linear 4-20mA DC output.

Model 1000 H2S Echem Instruction Manual Rev. 2.8 Page 2 of 30

Figure 3 Functional Block Diagram

Model 1000 H2S Echem

Figure 4 DM-624 Control Circuit

1.4 Base Connector Board

The base connector board is mounted in the explosion proof enclosure and includes: the mating connector for
the control circuit, reverse input and secondary transient suppression, input filter, alarm relays, lugless
terminals for all field wiring, and a terminal strip for storing unused programming jumper tabs. The alarm
relays are contact rated 5 amps @ 250VAC, 5 amps @ 30VDC and coil rated at 24VDC. Gold plated program
jumpers are used to select either the normally open or normally closed relay contacts.

Figure 5 Connector Board Terminals

Model 1000 H2S Echem Instruction Manual Rev. 2.8 Page 3 of 30

Model 1000 H2S Echem

1.5 Interference Data

DM-624 series electrochemical H2S sensors are subject to interference from other gases. This interaction is
shown in the following table as the relation between the amount of the interfering gas applied to the sensor,
and the corresponding reading that will occur (in ppm).

Gas Interference

Carbon monoxide 300ppm 1.5ppm
Chlorine 1ppm = -0.2ppm
Ethyl mercaptan 3ppm = 1ppm
Ethylene 100ppm = 0
Hydrogen 1% = < 5ppm
Hydrogen chloride 5ppm = 0
Hydrogen cyanide 10ppm = 0
Nitric oxide 35ppm < 2ppm
Nitrogen dioxide 5ppm = -0.5ppm
Sulfur dioxide 5ppm < 1ppm
Methyl mercaptan 2ppm = 1ppm

1.6 Explosion Proof Enclosures

The sensor is packaged in a cast metal explosion proof enclosure. The enclosure is fitted with a threaded cover
that has a glass lens window. Magnetic program switches located behind the transmitter module faceplate are
activated through the lens window via a hand-held magnetic programming tool allowing non-intrusive
operator interface with the sensor. All calibration and alarm level adjustments can be accomplished without
removing the cover or declassifying the area. Electrical classification is Class I; Div. 1; Groups C, D.

Flow Fault (optional)

Pump/Scrubber

Left

Power Supply/

Terminal PCB

+ +

24VDC

18-36

OUT

VDC

2.1A

IN

Right

Sensor (side view)

Sensor

Figure 6 Explosion proof enclosures

A 24VDC power supply and termination PCB for the power, relay contacts, 4-20mA output, and/or RS485
signal are located in the upper right explosion proof enclosure. The pump and optional low flow fault
assemblies are located in the upper left explosion proof enclosure. Declassify the work area before removing

covers.

Model 1000 H2S Echem Instruction Manual Rev. 2.8 Page 4 of 30

Model 1000 H2S Echem

2. Specifications

Sensor Type

Electrochemical cell

Measurement Range

0-10ppm H2S, up to 0-5 % H2S

Accuracy/Repeatability

±10% of reading or ±0.5ppm, whichever is greater

Response/Clearing Time

T80 < 1 minute

Operating Temperature

-40°F to +122°F: -40°C to +50°C

Outputs

Linear 4-20mA DC; RS-485 Modbus™; 3 relays (alarm 1, alarm 2, and fault), Contacts rated 5 amps

Input Voltage

110~220VAC; 18~36VDC

Power Consumption

700mA (16.8 watts)

Electrical Classification

Explosion Proof; Class I, Division 1, Groups C, D

Sensor Life/Warranty

Sensor: 6 month conditional warranty; Transmitter: 2 year warranty

Analyzer Weight

70 lbs.

Dimensions

29” X 29” X 8”

Model 1000 H2S Echem Instruction Manual Rev. 2.8 Page 5 of 30

Model 1000 H2S Echem

3. Installation

3.1 Mounting

Securely mount the Model 1000 analyzer panel or NEMA 4 enclosure (optional) in accordance with Figure 7.

Figure 7 Unit Dimensions

3.2 Gas Connections and Sampling System Notes

1. Install a length of tubing from the desired sample point to the sample input port (as shown in Figure 8).
Sample draw tubing should be 316 stainless steel of ¼" O.D.

NOTE: A constant pressure of 10±2psig should be provided to the analyzer for proper operation. In
applications where line pressure varies significantly, two-stage pressure regulation is recommended to
hold the constant pressure. Ideally, the pressure drop from the source to 10psig for analyzer should be
taken as close to the pipeline as possible. This speeds up response time to actual gas concentration
changes. An insertion probe membrane device is advisable to use for pipeline sources with high levels of
condensates, mist, and contamination.

Model 1000 H2S Echem Instruction Manual Rev. 2.8 Page 6 of 30

AIR AIR
INLET

MODELNO.

SERIALNO.

INPUTVOLTAGE

FREQUENCY

CURRENTLOAD

AREACLASSIFICATION

Model 1000 H2S Echem

PARTNO.

3200A-1ResearchForest Dr.
TheWoodlands,TX77381

www.detcon.com

detconinc.

AIR

FLOW

Calibrate

Cal Gas

H2S Vent

Pressure Gauge

Sample Inlet Port

These may be

combined into a

single vent

NOTE:

SAMPLE

FLOW

SAMPLEPRESSURE
10PSIG(CONSTANT)

SAMPLE

INLET

Sample

Sample Bypass and Liquid
Rejection Exhaust Vent.

Figure 8 Port Identification

2. Whenever possible, the Sample Bypass flow control valve of the Genie membrane filter should be used to
minimize the sample lag time between the sample tap and the analyzer location. It can also be used as a
means to exhaust condensed liquids in the sample line away from the Genie filter and prevent a “loss of
flow” condition. Set a flow of 100-200cc/min. and vent to a safe area using ¼” O.D. tubing.

3. Connect to the Over-pressure Relief valve and vent to a safe area. The pressure relief valve is set at
Detcon to open at 15-20psig. For convenience sake, the sample bypass and over-pressure relief can be
vented together.

4. Install a length of ¼" OD stainless steel tubing from the vent port to an area deemed safe for venting as
shown below. Venting pressure should be in the range of 0±1psig and ambient pressure is highly
preferred.

5. When the optional Acetic Acid Bubbler apparatus is used, prior to applying power and applying gas flow
the bubbler should be filled to the maximum fill level with a 5% acetic acid solution. (Standard white
vinegar is also acceptable).

Model 1000 H2S Echem Instruction Manual Rev. 2.8 Page 7 of 30