Related Manuals for PureAire ST-46 LEL
Summary of Contents for PureAire ST-46 LEL
- Page 1 Air Check ST-46 LEL Gas Monitor Instruction Manual PureAire Monitoring Systems, Inc. 1140 Ensell Road Lake Zurich, Illinois 60047 Phone: 847-726-6000 Fax: 847-726-6051 Toll-Free: 888-788-8050 www.Pureairemonitoring.com...
- Page 2 Our goal is to provide the best after sale service and support in the industry. That’s just one way PureAire takes that extra step to ensure your complete satisfaction.
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Page 3: Table Of Contents
PureAire Monitoring Systems, Inc. 10/25/07 Table of Contents 1: Introduction......................4 1.1 Component Identification ................5 1.1.1 Front Panel ..................6 1.1.2 Overall ..................... 6 1.1.3 Gas Sensor ..................6 2: Specifications ..................... 7 2.1 Performance Specifications ............... 7 2.2 Gas Detection Systems ................7 2.3 Signal Outputs ................... - Page 4 PureAire Monitoring Systems, Inc. 10/25/07 7: Appendix ......................20 7.1 Modbus RS-485 Serial Interface.............. 20 7.1.1 RTU Address ................. 20 7.1.2 Modbus Data Registers and Function Codes ......... 20 7.1.3 Modbus Configuration Software ........... 22 7.2 Alarm Relays ..................23 7.2.1 Alarm 3 (Sensor Fault Alarm) ..............
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Page 5: 1: Introduction
PureAire Monitoring Systems, Inc. 10/25/07 1: Introduction The Air Check EX is an explosion-proof toxic gas monitoring system designed for the continuous detection and measurement of toxic gas leaks. It is a single point monitoring system housed in an explosion-proof enclosure. The enclosure is suitable for use in Class 1, Group B, C, D and Class 2, Group E, F, and G hazardous areas. -
Page 6: Component Identification
Unity Key — Used for calibration when a new LEL sensor is installed. When a new LEL sensor is replaced, selecting the Unity key will center both the zero and span pots. For more information consult PureAire. -
Page 7: Front Panel
PureAire Monitoring Systems, Inc. 10/25/07 1.1.2 Overall Explosion-Proof Housing — Meets requirements for installation in Class 1, Group B, C, and D and Class 2, Group E, F, and G hazardous areas. Magnetic keypad permits calibration without declassifying area. Front Panel — Incorporates local digital display, magnetic keys, etc. See 1.1.1 above for front panel component details. -
Page 8: 2: Specifications
Disposable, LEL catalytic bead Response Time: Within 30 seconds to T90. Repeatability: ±10% of full scale. Operating Temperature: 14° to 113°F (0° to +40°C); consult PureAire for lower operating temperatures. Humidity: Typically 5 to 95% RH. 2.2 Gas Detection System Type: Proprietary catalytic bead. -
Page 9: Safety Characteristics
PureAire Monitoring Systems, Inc. 10/25/07 2.6 Safety Characteristics Transmitter enclosure suitable for Class 1, Group B, C, D and Class 2, Group E, F, and G hazardous areas. Also meets NEMA 4 with included O-ring. -
Page 10: 3: Installation
TB2. An earth ground lug inside the enclosure is provided for earth grounding of shied wires. PureAire recommends the use of a General Cable #E2203S.30.86 or equivalent for analog output and 24 VDC power input. The maximum permissible cable length is 0.62 miles (1 km). -
Page 11: Optional Outputs
PureAire Monitoring Systems, Inc. 10/25/07 3.3 Optional Outputs NOTE: The Air Check EX may be configured with one of the following optional outputs isolated 4-20 mA, Modbus serial output, SPDT alarm relays. Optional outputs are provided using an auxiliary, factory-installed electronics board. -
Page 12: Modbus Rs-485 Serial
PureAire Monitoring Systems, Inc. 10/25/07 3.3.2 Modbus RS-485 Serial Interface The Modbus RS-485 Serial Interface board allows up to 128 Air Check EX gas monitors to communicate to a Modbus master device on a single cable. The gas detector functions as a slave device; a PLC or PC running MMI or BUI software equipped with a Modbus driver functions as the master. -
Page 13: Alarm Relays
PureAire Monitoring Systems, Inc. 10/25/07 3.3.3 Alarm Relays The alarm option provides 5-amp resistive form C relays for Alarm 1, Alarm 2, and Alarm 3 conditions. They may be wired for either normally open or normally closed operation. IMPORTANT: The relay contacts are rated for 5 amp resistive loads. -
Page 14: 4: Normal Operation
PureAire Monitoring Systems, Inc. 10/25/07 4: Normal Operation The Air Check EX is a single point monitoring system designed for the continuous detection and measurement of toxic gas leaks. 4.1 Power Up Delay The Air Check EX incorporates a power up delay that holds the analog output at 4 mA for one minute after power is applied. -
Page 15: Alarm Reset
PureAire Monitoring Systems, Inc. 10/25/07 4.6 Alarm Reset If the instrument is equipped with the Alarm Relays option and one or more alarms are configured for latching operation (see Appendix), alarm conditions must be acknowledged by manually resetting the alarm. This manual alarm reset may be performed remotely via a control room signal or locally by holding the magnet at about the 7 o’clock position on the base of the cover assembly. -
Page 16: Routine Maintenance Schedule
PureAire Monitoring Systems, Inc. 10/25/07 4.8 Routine Maintenance Schedule Continuous gas detection systems depended upon to measure and detect hazardous gas leaks in the workplace require periodic maintenance to ensure proper operation. The frequency with which this routine maintenance is required depends on the environment, since temperature, humidity, gas concentrations, and dust all affect system operation. -
Page 17: 5: Maintenance & Calibration
The Air Check EX system requires periodic calibration with the appropriate standard gas. Calibration should be performed whenever 6 to 12 months has passed. 5.1.1 Optional Calibration Equipment The following equipment is available from PureAire to facilitate gas calibration: Part Number Description Quantity 6D360248 **... -
Page 18: Span Calibration Direct From Cylinder Gas
Connect p/n 690100 calibration cap to the LEL sensor cell. IMPORTANT: Be sure to perform the calibration with certified span gas and within the recommended use date. PureAire recommends that you verify that the concentration of the calibration gas is the same after calibration as it was before. -
Page 19: Displaying Zero/Gain Settings
PureAire Monitoring Systems, Inc. 10/25/07 5.1.5 Displaying Zero / Gain Settings The Zero and Span values applied during calibration may be read on the front panel of the LCD after exiting the Calibration mode. These values provide an indication of how much sensor sensitivity has declined over time — the higher the gain, the greater the degree of sensor sensitivity deterioration. -
Page 20: 6: Diagrams & Schematics
PureAire Monitoring Systems, Inc. 10/25/07 6: Diagrams & Schematics 6.1 Dimensional Drawing LEL catalytic sensor cell... -
Page 21: 7: Appendix
PureAire Monitoring Systems, Inc. 10/25/07 7: Appendix 7.1 Modbus RS-485 Serial Interface The optional Modbus RS-485 serial interface board allows up to 128 Air Check EX gas monitors to communicate to a Modbus master device — such as a PLC or PC running MMI or GUI software equipped with a Modbus driver —... - Page 22 PureAire Monitoring Systems, Inc. 10/25/07 Variable Alias Read Function Code Write Function Code A2D ASCII 31010 (6 bytes) 3 & 4 6 bytes of data representing the scaled span value, including the decimal point. The first 5 bytes contain the value; the last byte is a space. They are arranged with the first byte as the MSD with leading zero spacing.
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Page 23: Modbus Configuration Software
This is a one time requirement unless changes within the application necessitate adjustments after the initial installation. This functionality may be built into the Modbus master or may be performed with a portable computer running a simple software application. Consult PureAire for more information on this software. -
Page 24: Alarm Relays
PureAire Monitoring Systems, Inc. 10/25/07 7.2 Alarm Relays The Alarm option provides 5-amp resistive form C relays for Alarm 1, Alarm 2, and Alarm 3 conditions. IMPORTANT: The relay contacts are rated for 5 amp resistive loads. Appropriate surge suppressors should be installed across loads to prevent arcing on the contacts. -
Page 25: Alarm Relay Configuration
Alarm 3 = Fault Alarm 3 = Trips with Alarm 2 IMPORTANT: PureAire recommends that Alarms 1 and 2 always be set for High Trip (activate when measured gas value rises about setpoint) except for instruments monitoring for oxygen deficiency. Setting these alarms for Low Trip will cause them to... -
Page 26: Connecting Remote Digital Display
The Remote Display Alarm Indicator is designed to display remote LEL percent concentration information from PureAire’ Combustible monitors. All PureAire Combustible LEL monitors have a built in 4-20mA output. The remote display alarm easily connects to the monitor’s input power and mA output connection. - Page 27 PureAire Monitoring Systems, Inc. 10/25/07 Mount the case to a wall or other flat surface. There are 4ea. through holes for fastening the case. The case is designed to be flush mounted. NOTE: The front cover can be removed from the case by gently pulling on the plastic hinges.
- Page 28 Entering the set up menus will disable the real time LEL readings After wiring the remote display to your LEL monitor, turn on the power to your ST-46 LEL monitor. During the warmup the remote display will illuminate a yellow fault LED and the display will read FL , (indicating that the monitor is in fault).
- Page 29 PureAire Monitoring Systems, Inc. 10/25/07 How to set the zero and full scale range This will need to be set up in the field to adjust to the length of cable between the combustible LEL monitor and the remote display alarm indicator. (See Section 3.3 Optional outputs 4-20mA loop).
- Page 30 PureAire Monitoring Systems, Inc. 10/25/07 CAUTION: If the LEL monitor is in the measuring mode and the ZERO push button is pressed on the remote digital display, an “Err” will be displayed on the remote display and no readings will be recorded. If the SPAN push button is pressed in the measuring mode, the remote display will automatically adjust to full LEL scale.
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