Dew Point Mirror 373 OPERATION AND MAINTENANCE MANUAL MBW Calibration Ltd. Seminarstrasse 57 CH-5430 Wettingen / Switzerland +41 56 426 21 33 phone +41 56 427 14 00 fax 0Hwww.mbw.ch info@mbw.
Warranty MBW Calibration Ltd. (MBW) warrants the products it manufactures or distributes to be free of defects in material and workmanship under normal use and service when operated within the specified design limitations for a period of 12 months from date of initial shipment.
Table of Contents Table of Contents ............................................................................................................................ i Welcome .......................................................................................................................................... 1 How to Use This Manual ................................................................................................................ 1 For More Information ........................................
Preparation for Use ...................................................................................................................... 31 Benchtop Use.............................................................................................................................. 31 Rack Mounting ............................................................................................................................ 32 Preparation for Shipping or Transportation ...........................................
Welcome Congratulations! With the 373 Dew Point Mirror you will be able to perform precision dew point and frost point measurements as well as measurements of other parameters such as relative humidity. The 373 utilizes a full color active matrix liquid crystal display with an integral touch panel. It has a high contrast ratio and a wide viewing angle for easy readability. Data is displayed in large easy to read fonts.
Operation Getting Started This section allows you to set up and start using the 373 right away. You’ll turn the system on and quickly familiarize yourself with the layout and features of the display and touch screen. Next, you’ll learn about the optical mirror assembly for later care and cleaning that may be required. Finally, you’ll use the 373 to measure the dew point temperature. Set your 373 on the bench and let’s get started! Turning the 373 On and Off The 373 needs a source of normal AC power.
Data Lines The first five lines of the display are for numeric or graphic representation of the measured data. We refer to those first five lines as data lines. Relative Humidity % 9.50 -9.8 -10.2 -9.65 If numeric, a data line contains the value to the left, with the parameter description and units to the right. If graphic, a data line shows a simple graph of the data over time. Time Span 00:30:00 20.16.
The Touch Screen The 373 utilizes a touch screen for user interaction. To activate a menu option or toggle a function on or off, simply touch the screen directly over the key or object desired. Calibrate the Touch Screen Before using the 373 for the first time, you may need to calibrate the touch screen to your finger positioning preference. Here’s how – 1. Press and hold the enter key on the numeric keypad for 3 or 4 seconds. If you’ve done it correctly, you’ll hear two loud short beeps.
Selecting Parameters to Display Selecting which parameters to display on the five data lines is easy. It is done with the Parameter menu. 1. Use the lower right menu key to select the Parameter menu. ‘Parameter’ appears on the key, and the keys above get left pointing arrows. Notice that each key corresponds to the data line it points toward. 2. Press the arrow key corresponding to the data line you wish to change. Notice that each time you press the arrow key, the parameter of the data line changes.
this is not required and nothing is wrong with leaving the Units menu (or any other menu) on the screen. The Measuring Head Assembly The heart of the 373 Dew Point Mirror instrument is the measuring head assembly. It is designed to be highly sensitive and accurate, yet rugged and easily accessible for periodic mirror cleaning.
Measuring the Room Ambient Dew Point Temperature Dew/Frost Control Lets use the 373 to measure the dew point temperature of the room by enabling the portion of the system responsible for cooling and maintaining the mirror at the dew or frost point temperature. Do so by pressing the Dew/Frost Control key.
Gas Inlet Connection While the previous example did not rely on any external gas connections, the 373 is equipped with fittings for connection of gas inlet and outlet tubing. This allows the 373 to measure the dew or frost point of chambers and other devices that can be connected to it via tubing. If you have a gas source you wish to measure, such as a humidity generator or chamber, connect a tube between it and the 373 gas inlet on the back of the unit.
Swagelok® Tube Fittings Swagelok® brand tube fittings are generally used to connect the gas inlet and outlet tubes to the 373S, H, and HX systems. Depending on the configuration of your specific 373, the back panel fittings are either ¼” or 6 mm. When ordering tube fittings from your local Swagelok® supplier, be sure to specify the correct size for your instrument. Swagelok® tube fittings come to you completely assembled, finger-tight and ready for immediate use.
When using an Original-style Gasket, place it into the female nut whenever possible. No special positioning is needed because the gasket is self-aligning. When using a Gasket Retainer Assembly, press the assembly onto the gland as shown. The retainer assembly will locate the gasket over the bead and hold it in place. Be careful not to scratch or nick the bead. Damage to the bead may cause leakage. To assemble the connection, hold the male nut or body hex stationary. Tighten the female nut finger-tight.
System Configuration You may configure many aspects of the 373 based on your preferences at the time. For instance, you may easily select which humidity, temperature, and pressure values to indicate on the screen, the order in which they should appear, their units, and whether each will be shown as a number or as a graph. In addition to display configuration, you can also change how the 373 performs it’s control functions such as Dew/Frost determination, ORIS control, tube heating, mirror pre-cooling, etc.
Display Parameters Use the Parameters menu to select which parameters to display on the data lines. When you select parameters for display on any of the five data lines, those selections remain valid until you change them again, even if you turn the 373 off. See Selecting Parameters to Display on page 6 to select which values to display. A list of the available parameters follows. Note that not all parameters are available on all systems since some systems may not contain the associated hardware components.
The time span is changed with the Numeric/Graphic menu. 1. Use the lower right menu key to select the Numeric/Graphic menu. ‘Numeric/Graphic’ appears on the key, and the key directly above it shows ‘Time Span’. 2. Press the Time Span key. A dialog box appears for entry of the desired time span. 3. Use the numeric keypad to enter a new value. As you press each numeric key, the numbers appear in the white Change To field of the dialog box. 4.
4. Using the numeric keypad, enter the value needed. If the number shown in the Value column is already correct, no entry is needed here. If you make a mistake while entering the value, use the touch screen and press on the number in error. Each time you press the touch screen there, the number will backspace one, erasing the flawed digits. 5.
Now enable or disable the Force Frost function by pressing the Force Frost Below button. A green indicator light on the button means that the function is enabled. If the light is not illuminated, then the Force Function is disabled, and no Force Frost will be performed. Complete your preference by pressing Ok or the keypad’s enter key.
Heating Time The Heating Time determines how long to hold at the mirror check temperature before allowing another dew or frost point measurement. A heating time of 0 results in no hold, meaning that once the mirror check temperature has been reached, the function ends and dew/frost control resumes immediately. If a heating time greater than 0 is entered, then the mirror will heat and remain at that temperature for the duration of the heating time value.
2. All systems, including L and LX models, are equipped with controls for the head heater even if not equipped with external tube heater controls. This is done to allow those systems to automatically maintain the head temperature at or above 20°C as mentioned in the previous note. If you enter a head heater setpoint, enable the control, and turn on the heater, you may heat the head to values higher than 20°C.
Temperature Units Temperature values may be displayed in units of °C, °F, or K. When changing temperature units, all temperature values, whether displayed as numeric or in a graph, change to reflect the new units selection. Notice that the chosen units will appear on the screen both on the units selection key and next to any temperature related values currently displayed.
Changing Color You are free to change the foreground and/or background color of any data line with the Fore Color and Back Color menus. Access the Fore Color and Back Color menus with the menu selection key discussed in the Menu Keys section on page 4. Like other system settings, these color changes are retained. To revert to the standard system default color scheme, press and hold the 9 key for a few seconds while in the Fore Color or Back Color menu.
Analog Outputs The 373 is equipped with at least two analog outputs that are independently configurable. For each of the analog outputs, you may easily select which parameter to track and how to scale the selected parameter to the analog output range. These selections are made for each of the analog outputs via the Analog Outputs menu. 1. Access the Analog Outputs menu with the menu selection key discussed in the Menu Keys section on page 4. 2.
Scaling the Output to the Data With the appropriate configuration window displayed, you may change the data scaling of the analog output vs. the parameter. Continuing with the example in the previous paragraph, assume that you wish to have 0 to +1 VDC on the analog output represent 0 to +100 %RH.
Back Panel Connections Power Plug The power requirements are identified on the serial number label on the back of the instrument. Depending on the model, fuse access may also be available on or near the power plug. Power Switch Depending on the model, the main power switch will either be mounted on the front panel (L and LX models), or on the back panel near the power plug. Use the power switch to turn the system ON and OFF.
Mirror Temperature The mirror of the 373 is equipped with two independent temperature sensors. One is used for system measurement and control. The wires of the other sensor are brought directly to the back panel’s Mirror Temperature connector and are for your use. Using this connection, you may measure the mirror temperature sensor directly without affecting normal system operation. The wires internal to the 373 are shielded up to the connector.
Gas Input and Output The gas input and output fittings are used for connection of the 373 to the sample gas. Based on the original configuration of your system, it will generally contain ¼” or 6 mm Swagelok® tube fittings, or ¼” Swagelok® VCR® metal gasket face seal fittings. While a connection to the gas input is most likely required, the gas output connection is often left unconnected. If the fittings are capped, you’ll need to remove those caps for operation or connection of sample lines.
Measurement Tips Since each particular 373 model is best suited for a specific dew/frost point range, it is important to have some minimal knowledge of the expected value of the measurement in order to ensure that the proper system is being used. In addition to proper system selection, your success will depend on other factors as well, such as selection and connection of hoses, cooling and/or heating requirements, flow rate, mirror cleanliness, and dew vs. frost determination.
Connecting Hoses Your success with dew or frost point measurement may likely depend on proper selection and connection of the hoses you use in configuration of your gas sampling system. Types of Hoses There are various types of hoses available for use in your gas sampling system. You should consider the suitability for your application. Teflon Teflon tubing is flexible, easy to use, and is well suited for frost/dew point measurements in the range of approximately –60 to +20 °C.
Hose Input and Output Preferred Connections When comparing two or more instruments, make the connections in parallel. Pr Flow Pump Pr Flow Pump Troublesome Connections Never connect instruments in series, because of the interference of the two instruments.
Cooling Requirements Air Cooling Mid and high range systems are equipped with air cooling. When air cooled, the fan speed is controlled automatically by the computer. Air cooling is generally sufficient for measurements of frost/dew points from approximately –40 to +95°C. Air cooling operates automatically and requires no user input. Water Cooling In addition to air cooling, many mid and high range systems are also equipped with auxiliary water cooling connections.
External Hose Heat The 373H and 373HX systems are equipped with controls for externally connected heated hoses. These external heated hoses allow sampling of gas with a dew point temperature that is higher than room temperature. The external heated hoses are used in conjunction with head, block, and inner tube heater control. Use of an external heated hose connected to the Gas Input is required for high dew point measurements.
Installation Facility Requirements Environmental Your 373 is a precise laboratory quality instrument. While it does not require any special environmental control, it works best when the temperature is stable and free of rapid transitions. For operation, it is best to keep the operating conditions within the following parameters if possible.
Rack Mounting Rack mounting kits are available for all 373 models. For 373LX models, simply remove the unit from it’s current rack mount housing and reinstall it into the rack of your choice. Due to it’s weight, you should support it on the sides or rear with rack guides that should be available from the supplier of your rack system. For all other models, rack mount adapters are available. Consult the factory for pricing and availability.
Remote Communication Introduction The 373 is equipped with a bidirectional RS-232 communications interface that allows it to be connected to a remote computer. This section is intended to provide necessary information for programming personnel regarding the use of the interface, including the hardware connections, communications settings, and the command syntax. Hardware Connection & Cabling Connect a computer to the 373 using a standard RS-232 9-pin extender cable.
Command Syntax This section details the general syntax guidelines regarding termination, leading and trailing spaces, case sensitivity, and numeric values. Throughout this section, characters originating from the computer will be shown for illustrative purposes in this font. Characters originating from the 373 will be shown in this font. General Usage All commands require either a question mark or an equal sign to indicate whether you are requesting data or setting new setpoints or parameters.
Leading and Trailing Spaces The 373 ignores leading and trailing spaces. It also ignores spaces before and after equal signs and question marks. For example, each of the following commands is perfectly valid. Dp?CR Dp ? CR Pump.on=1CR Pump.on = 1 C R However, the following commands are invalid since spaces are embedded within the keywords. D p?CR Pu mp.on=1CR Case Sensitivity All commands are insensitive to case.
Command Reference The available commands listed here are grouped by function. If a command is considered as a read only value, then it is shown with a question mark only. For instance, the following is considered as read only and does not have the ability to be set. Dp? A command that has both read and set capability is shown in a slightly different manner. The question mark and equal signs are shown for illustrative purposes within brackets. Those brackets indicate that either one or the other is required.
Commands Listed By Functional Group Measurement Data Syntax DP? FP? RH? RHw? PPMv? PPMw? AH? SH? VP? P? Pa? Flow? Tx? Tp? Tm? Th? Om? Ox? Function Dew Point, °C Frost Point, °C Relative Humidity, % Relative Humidity (WMO), % Volume Ratio, PPMv Weight Ratio, PPMw Absolute Humidity, g/m3 Specific Humidity, g/kg Vapor Pressure, Pa Head Pressure, Pa Atmospheric Pressure, Pa Flow Rate, l/m External Temperature, °C Precooler Temperature, °C Mirror Temperature, °C Head Temperature, °C Mirror PRT Resistance, Ohms
Mirror Cleaning Preparation Syntax MinHeadRemovalTemp[=n][?] SaveCfg=373 Function Head and inner cooler are warmed above this temp when Mirror Cleaning button has been pressed prior to head removal, °C Save these and other configuration parameters Automatic Mirror Check Syntax AMC.on[=i][?] AMC.cycleTime[=n][?] AMC.heatTime[=n][?] AMC.temp[=n][?] AMC.
Precooler Control Syntax PreCoolerPID.on[=i][?] PreCoolerPID.setPt? PreCoolerPID.fixedSetPt[=n][?] PreCoolerPID.deltaSetPt[=n][?] PreCoolerPID.fixedOn[=i][?] PreCoolerPID.
Mirror Temperature Calibration Coefficients Syntax MirrorTempCal.r0[=n][?] MirrorTempCal.a[=n][?] MirrorTempCal.b[=n][?] MirrorTempCal.c[=n][?] MirrorTempCal.avg[=n][?] MirrorTempCal.avgBand[=i][?] MirrorTempCal.sensCode[=i][?] MirrorTempCal.coefType[=i][?] SaveCal=373 Function Callendar VanDusen R0 coefficient, ~ 100.00 Callendar VanDusen A coefficient, ~ 3.9083e-3 Callendar VanDusen B coefficient, ~ –5.775e-7 Callendar VanDusen C coefficient, ~ -4.
Internal Tube Temperature Calibration Coefficients (if so equipped) Syntax IntTubeTempCal.a0[=n][?] IntTubeTempCal.a1[=n][?] IntTubeTempCal.a2[=n][?] IntTubeTempCal.a3[=n][?] IntTubeTempCal.avg[=n][?] IntTubeTempCal.avgBand[=i][?] IntTubeTempCal.sensCode[=i][?] IntTubeTempCal.coefType[=i][?] SaveCal=373 Function Polynomial 0th order (Zero) coefficient, ~ 0 Polynomial 1st order (Span) coefficient, ~ 0.
Relative Pressure Sensor Calibration Coefficients (if so equipped) Syntax RelPressCal.a0[=n][?] RelPressCal.a1[=n][?] RelPressCal.a2[=n][?] RelPressCal.a3[=n][?] RelPressCal.avg[=n][?] RelPressCal.avgBand[=i][?] RelPressCal.sensCode[=i][?] RelPressCal.
Maintenance Mirror Cleaning The heart of the 373 dew point measuring instrument is the measuring head assembly. It is designed to be highly sensitive and accurate, yet rugged and easily accessible for periodic mirror cleaning. Removing the Head Cover Screw or Retaining Bar The measuring head is located on the right side of the 373 front panel. To gain access to the mirror and optoelectronic components, you must first remove the cover screw or the retaining bar.
Inspecting / Cleaning the Mirror The mirror requires occasional periodic cleaning to maintain high accuracy measurements. The flush mounted mirror is easily accessible by removing the cover screw and optical mirror assembly. Look at the mirror with the naked eye or with a magnifying glass. If signs of contamination are present, or suspected of being present, use the following procedure to clean the mirror. 1. Clean the mirror with a clean cotton swab or lint free tissue dampened with distilled water. 2.
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