PEMTECH PT605 User manual

Gas Detection Technology
PT605
Dual Gas Analyzer
H2S & CO2
Revision 7
February 2010
Operator’s
Manual
Pem-Tech, Inc.
Houston, Texas
U.S.A
www.pem-tech.com

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Table of Contents
Sections Page No.
Specifications 5
Operation 6
Overview 7
PT605 Analyzer –Block Diagram 7
Figure 1. PT605 –Unit Layout 9
Front Panel 10
Clear Cycle 11
H2S Sample Cycle 11
Messages and reading display during 11
Normal sampling cycle
Alarm LEDs and keypad switches 12
Installation and Unit Startup 13
System Wiring 13
Power Supply Input 15
AC Power Input 15
DC Power Input 15
4-20mA Analog output 15
User connection and wiring diagram 16
Alarm Relay contacts 17
RS232 / 485 Serial Communication 17
Connecting Gas stream to the Analyzer 17
Unit startup check list 18
STOP –Important Installation and 19
Maintenance note
Sensor Calibration 20
H2S Sensor Calibration 21
Sensor calibration procedure 21
Tips on good calibration 23
Sensor calibration errors 23
CO2 Sensor Calibration 24
Sensor calibration procedure 25
Tips on good calibration 27
Sensor calibration errors 27
(continue on next page)

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Table of Contents (continued)
Sections Page No.
Fine tuning of 4-20mA analog output 28
Alarm Relays 29
Programming Alarm levels 29
MODBUS RTU Communication 31
Edit / Assign unit address 31
MODBUS Communication and 32
Data register list
Replacing Analyzer Sensor Assembly 34
Care 35
Maintenance 35
Spare Parts List 36

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NOTICE
PEM-TECH INCORPORATED SHALL NOT BE LIABLE FOR TECHNICAL OR
EDITORIAL ERRORS OR OMISSIONS MADE HEREIN, NOR FOR INCIDENTAL OR
CONSEQUENTIAL DAMAGES RESULTING FROM THE FURNISHING,
PERFORMANCE, OR USE OF THIS MATERIAL.
LIMITED WARRANTY
Pem-Tech, Incorporated warrants all the equipment to be free from defects in
workmanship and material. The products will operate in conformance with the
published specifications when subjected to intended and proper usage for the period of
one (1) year from the date of shipment.
The warranty provides only the benefits specified and does not cover defects which
result from acts beyond the control of PEM-TECH including, but not limited to: damage
by accident, negligence, tampering, or failure to operate in accordance with the
procedures outlined in the Operations Manual. PEM-TECH’s liability under no
circumstances will exceed replacement of the unit claimed to be defective.
Tampering with the equipment and altering it for uses other than the intended use or
replacement of parts not supplied by the company, shall immediately void and cancel
all the warranties with respect to the affected products.
The warranties specified herein are in lieu of any and all other warranties, express or
implied. In no event, whether as a result of breach of warranty or alleged negligence,
shall PEM-TECH be liable for special or consequential damages, including, but not
limited to, loss of profits or revenue, loss of equipment or down time costs.

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SERVICE POLICY
Pem-Tech has service facility at the factory. For all the repairs contact at our toll free
number 1-800-379-3894 or visit our website www.pem-tech.com
For all repairs call us for a Return Material Authorization number (RMA). Inform us
briefly the nature of the problem and obtain shipping address. Properly pack the
equipment before shipping. Also include your complete shipping address and contact
name and phone number.
For non-warranty repairs you must provide the limit to repair costs. State if a quote for
repair cost is required before you can authorize the repair cost. For this an additional
charge may be applicable.
NOTE:
1. For all the repairs under warranty, serial number must be legible on the items being
repaired.
2. Shipping point is FOB Houston.

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SPECIFICATIONS
Typical Range: H2S: 25 ppm, & 200 ppm
CO2: 5%, 10%
(Other Ranges also available)
Range is pre-programmed at the factory
Electrical Classification: Class I Div 1, Suitable for use in Hazardous
Location
Weight 70 Lbs (31.8 Kg)
110 Lbs (49 Kg ) with Fiberglass enclsoure
Sample Gas Physical properties: Dry and particle free
Temperature: 10 F to 110 F (4 C to 50 C)
Sample inlet Tube Fittings: ¼” Stainless Steel tube fittings
Repeatability: When challenged with same calibration gas,
H2S: within 0.5 ppm (analyzer with 25 ppm range)
2 ppm (analyzer with 200 ppm range)
CO2: within 0.2 %
Accuracy: 3 %
Alarm Relays: 3 SPDT fully programmable dry relay contacts Form “C”
Type . Rated 5 amps @ 125 VAC or 24 VDC
Analog Output: 4-20 mA ( 350 maximum loop resistance )
Display: 4 lines by 16 character LCD display with backlight
Supply Voltage: 18-28 VDC
117 VAC (240 VAC option available)
Power Consumption: < 4.5 watts

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Sampling System Junction Box
Main Electronics and Control Assemblies
Termination / User
connection Box
Dry Sample in
¼ Tube Fitting
vent
Air Intake
PT605 Analyzer –Block Diagram
OPERATION
Overview
The following figure illustrates an overview of the units operation. Refer to figure 1 for
complete system layout.
When the power is applied to the unit it will display startup messages such as current alarm set
points, background or interference gas settings and sensor calibration data.
After the startup messages the system will begin the warm up cycle for approximately 10
minutes (600 seconds). This allows the sampling system to clear and perform initial diagnostic
tests.
H2S Measurement: For the measurement of H2S concentration the analyzer performs sample &
purge routine. The analyzer samples the on-stream gas for 90 seconds and then purges for 180
seconds. At the end of sample cycle the internal solenoid valve is switched off and ambient air
is pumped into the sampling system to purge. The final H2S reading is updated on the display,
4-20mA output is generated and alarm relays are energized if the H2S concentration exceeds
the preset alarm levels.
Sample Conditioning
Pressure Regulators
External Filters
CO2
Sensor Asmbly
Main CPU Board Assembly
Control Logic
Flow Meter +
Coalescing Filter
H2S
Sensor Asmbly
Solenoid
Valve
Gas Sample
routing & Vent
block with tube
Purging Pump
Terminal Blocks
4-20mA
Alarm Relays
AC / DC power Input
Sensor Signal conditioning
AC-DC , DC-DC power convertors. Alarm
relays

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CO2Measurement: The measurement of CO2is continuous. The on-line gas is continuously
being diffused into the Infra-red CO2sensor sampling assembly. The CO2 reading is updated
every second on the display. Also 4-20mA is generated and alarm relays are energized if CO2
concentration exceeds the preset alarm levels.
Note:
In an installation where ambient air is contaminated with H2S and other toxic gases, it is recommended
that clear instrument air must be used. The instrument air should be connected to the air intake located
below the sampling system enclosure.

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Figure 1. PT605 Analyzer in fiberglass enclosure. Complete unit layout
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Front Panel
PT605 front panel is equipped with a large liquid crystal display with back light, four alarm
LEDs for visual alarm indicators, and keypad switches. The H2S & CO2concentration and
sample and clear mode are displayed on the LCD. The keypad switches are used to reset
alarms, calibrate sensors and program unit configuration.
Following are the prompts and messages on the LCD during sample and clear cycle.
Front Panel Assembly
LCD Prompts & Messages
During Clear Cycle During Sample Cycle
The first and second line on the LCD displays the concentration of the H2S and CO2. The third
line indicates when the analyzer is sample or Purge mode for the H2S measurement. The last
line indicates the status or signal strength of the sensors. If in clear cycle E1 is the signal level
for the H2S sensor while E2 is the signal level of the CO2 sensor. If the analyzer is in H2S
sampling mode then the last line indicates the change is H2S sensor signal in ppm and voltage.
In Clear Cycle as the sensor is purged with air the E1 reading would decrease while during the
H2S = 00 ppm
CO2 = 00 %
Clear Tm 30 Sec
E1=0.90 E2= 0.40
H2S = 00 ppm
CO2 = 00 %
Sample Tm 30 Sec
2.0 ppm * 1.2V
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