RH G3 User Manual
  1. Manuals
  2. Brands
  3. RH Manuals
  4. Portable Generator
  5. G3
  6. User manual

RH G3 User Manual

Low humidity generator
Hide thumbs
Table of Contents

Advertisement

Quick Links

Download this manual
G3
Low
Humidity
Generator
User Guide
Document:
G3 Manual
4/26/2024
Page 1 of 87
RH Systems, LLC

Advertisement

Table of Contents
loading
Need help?

Need help?

Do you have a question about the G3 and is the answer not in the manual?

Questions and answers

Subscribe to Our Youtube Channel

Summary of Contents for RH G3

  • Page 1 Humidity Generator User Guide Document: G3 Manual 4/26/2024 Page 1 of 87 RH Systems, LLC...
  • Page 2 Document: G3 Manual 4/26/2024 Page 2 of 87...

  • Page 3: Table Of Contents

    Introduction ..........................6 Background of Humidity Generation ..................... 6 Two-temperature principle ......................6 The RHS hybrid two-pressure, two-temperature principle ............. 7 G3 Design ............................8 Common Defining Equations ....................... 11 Humidity Equations ........................13 System Identification and Component Location ..............17 Front panel ............................
  • Page 4 Idle mode ............................36 Power off ............................37 Operation ..........................38 G3 Operation using RHS Control ....................38 Apply Vacuum ..........................40 Fill, Purge, and Chill ........................41 Selecting Humidity Control Mode ....................43 Changing Set Points ........................45 Purge mode ........................... 46 Generate mode ..........................
  • Page 5 Document: G3 Manual 4/26/2024 Page 5 of 87...

  • Page 6: Introduction

    The RH Systems G3 Humidity Generator is a system capable of continuous, high-accuracy humidity generation over a wide range of humidity, temperature, and flow rates. The G3 design is an RHS hybrid two-pressure two-temperature system based on the fundamental two-pressure principle originally developed by NIST.

  • Page 7: The Rhs Hybrid Two-Pressure, Two-Temperature Principle

    Since computing power is generally not a limiting factor, it is always best to use the mathematics of combined two-pressure, two-temperature principles in determining all generated parameters. Document: G3 Manual 4/26/2024 Page 7 of 87...

  • Page 8: G3 Design

    (generally at the DUT), are all that is required to determine the resulting humidity content. The G3 receives an input gas (or carrier gas) at its Gas Inlet connection on the rear panel. Gas is mechanically regulated to a manually set pressure which is displayed on the mechanical pressure gauge P and is also measured electronically on the air-in pressure sensor Pai.
  • Page 9 DUT. The G3 has a unique design based on the compact FPSC Stirling cooler units utilized for saturator cooling. Typical outlet temperatures needed from the Stirling coolers are +10 °C to as low as -100 °C.
  • Page 10 DUT. In the case where both the saturator and DUT temperatures are required, uncertainty of both temperatures must be considered. Figure 4—Thermal diagram of the G3 two-pressure, two-temperature system. Saturator temperature is maintained by control of the Stirling coolers attached to the inlet and outlet plates of the saturator, and by heaters attached in the same locations as depicted in figure 4.

  • Page 11: Common Defining Equations

    �� ��=0 where e is the saturation vapor pressure (in Pascals) over liquid water in the pure phase T is the temperature in Kelvin = –2.8365744·10 = –6.028076559·10 G3 = 1.954263612·10 = –2.737830188·10 –5 1.6261698·10 –10 7.0229056·10 –13 = –1.8680009·10 2.7150305...
  • Page 12 –4 –4 9.5972907·10 8.6786223·10 = –4.1935419·10 –6 = –3.5912529·10 –6 –9 –9 6.2038841·10 5.0194210·10 = –1.0385289·10 = -8.2308868·10 –1 –1 8.5753626·10 5.6519110·10 –3 –3 = –2.8578612·10 = –1.5304505·10 –6 –6 3.5499292·10 1.5395086·10 Document: G3 Manual 4/26/2024 Page 12 of 87...

  • Page 13: Humidity Equations

    = –2.4363951·10 Humidity Equations The following equations are used in the G3 to calculate various humidity parameters. These equations are not approximations, but rather account for the temperature differences between the saturator and chamber, and the non-ideal behavior of water vapor when admixed with air or other gases.
  • Page 14 7 for ice, to compute T. Call this value the frost point temperature T d. Use the frost point temperature T , chamber pressure P , and Equation 4 for ice to compute the dew or frost point enhancement factor  Document: G3 Manual 4/26/2024 Page 14 of 87...
  • Page 15 �� �� ∙ �� ∙ �� �� �� �� �� �� ∙ (15) �� �� ∙ �� �� �� �� Document: G3 Manual 4/26/2024 Page 15 of 87...
  • Page 16 �� ∙ �� ∙ �� �� �� �� �� = (16) ( �� ) + �� �� − �� ∙ �� ∙ �� ∙ �� �� �� �� �� �� �� �� Document: G3 Manual 4/26/2024 Page 16 of 87...

  • Page 17: System Identification And Component Location

    The G3 System comes with a built-in VESA mount PC. The PC is internally mounted within the rear of the G3 (or on the back of the monitor). The PC runs RHS Control software which is used for G3 control and data collection.

  • Page 18: Inside View, Cover Panels Removed

    Inside view, cover panels removed Rear view without panel Left view without panel Front view without panel Right view without panel Document: G3 Manual 4/26/2024 Page 18 of 87...

  • Page 19: Major System Components

    Major System Components     Document: G3 Manual 4/26/2024 Page 19 of 87...
  • Page 20 9 Top Vacuum Flange Part A 10 Top Vacuum Flange Part B 11 Bottom Vacuum Flange 12 Generate & Purge - 3 Way Valve 13 Gas Inlet Pressure Regulator Assembly 14 Pressure Sensor Manifold Assembly Document: G3 Manual 4/26/2024 Page 20 of 87...

  • Page 21: Installation

    3.1.4 Floor Space The G3 requires a floor space of approximately 1.5 m x 2 m. This allows adequate space to the sides and rear of the unit for operation, service, and utility connections. The G3 is supplied on rolling casters for ease of positioning.

  • Page 22: Uncrating

    The G3 is shipped in a padded wooden shipping container. The front door doubles as a ramp to remove the G3 more easily from the crate. The G3 casters allow it to be rolled out of the crate, down the ramp, and onto the floor.

  • Page 23: Install Monitor (And Keyboard/Mouse If Desired)

    2. Slide the mounting end of the monitor arm over the top of the mounting pole and slide the arm down over the pole. Document: G3 Manual 4/26/2024 Page 23 of 87...

  • Page 24: Remove Front, Back, And Side Panels

    USB ports on the G3 Monitor Panel. 5. Turn the mouse and the keyboard on (their switches are generally found underneath them). Remove front, back, and side panels The system has removable panels allowing access to internal components.

  • Page 25: Removing Shipping Bracket

    3. Using a 6 mm hex key, remove the 4 screws at the back of the shipping bracket. Remove the bracket from the G3. 4. Save the bracket, screws, and washers for future shipping of the G3. Document: G3 Manual...

  • Page 26: Back Panel Gas Connections

    For example, if you have only 50 psi input pressure, try setting the regulator no higher than about 45 psi. This ensures the G3 has enough headroom to properly regulate the incoming gas. Document: G3 Manual...

  • Page 27: Leveling Vacuum Chamber

    Leveling Vacuum Chamber A reference bubble level is applied to the top of the vacuum chamber. Each caster wheel on the bottom of the G3 has a rotating knob that lowers an adjustable pad onto the ground for leveling purposes. If more than ½ of the bubble lies...

  • Page 28: Checking Vacuum Chamber Supports

    ON. To do so, toggle it to the position. This makes the AC circuit inside the system live, but the G3 will not fully energize until the main power switch on the front panel is also enabled.

  • Page 29: Quick Start

    Introduction to RHS Control RHS Control is a PC program (available on Windows and Linux) which allows for operation of the G3 system. Operation may be manual, through direct entry of desired setpoints, or automatically, through a series of preprogrammed, user selectable setpoints and times. The short sequence that follows will guide you quickly through a successful frost point generating session.

  • Page 30: Initialize Vacuum

    4.2.2 Control Window Once the G3 is connected, its control window appears. From this window, it is possible to enter various setpoints of humidity, pressure, temperature, and flow as well as enable/disable vacuum and cooling functions. It also allows for operation modes of Generate, Purge, Fill, and Vent.

  • Page 31: Purge

    Purging the tubing, connections, and instruments following the saturator removes unwanted water, water vapor, and condensation that could adversely affect the generated or measured humidity. Before initial humidity generation, or before cooling the saturator, purge the G3. a) Using the drop-down selector as shown, select [FP] Frost Point as the humidity control mode.
  • Page 32 Frost Point setpoint to a lower value, such as -50 °C to allow the saturator to cool and cause the water to freeze. Notice that the Upper and Lower Sat Temperature setpoints compute automatically. Document: G3 Manual 4/26/2024 Page 32 of 87...

  • Page 33: Generate

    If devices connected to the gas outlet ports are showing humidity reading above the current setpoint value while the G3 is in PURGE mode, additional purge time is likely required. While in purge mode, connected devices will generally indicate values lower than the G3 setpoint, indicating the purge is working.

  • Page 34: Viewing Additional Data

    3. In this example, the Humidity Values data group was selected. You may view any data group at any time without affecting the operation of the system. Document: G3 Manual 4/26/2024 Page 34 of 87...

  • Page 35: Plotting Data

    Select the Graph icon at the bottom of the screen. A data selection window appears. b) Select an instrument (the G3) on the left side and any number of data items on the right side. c) Close the window. A graph appears.

  • Page 36: Idle Mode

    Idle mode The G3 performs best if it is allowed to remain operating at a set temperature with a small flow rate even when its generated output is no longer required. This allows the gas path tubing and connections to remain dry (or conditioned at a desired humidity) so that it is immediately ready to generate when next needed.

  • Page 37: Power Off

    4. Turn off any pressurized gas source that is connected to the system gas inlet. When restarting the system after a period of full power down, follow steps in section 4 to re-establish a dry, evacuated, operational system. Document: G3 Manual 4/26/2024 Page 37 of 87...

  • Page 38: Operation

    5 Operation G3 Operation using RHS Control RHS Control is a PC program (available on Windows and Linux) which allows the user to operate the G3 system. The system may be operated manually, through direct entry of desired setpoints, or automatically, through a series of preprogrammed, user selectable setpoints and times.
  • Page 39 5.1.2.1 Connect the G3 When the Connection window opens, it initiates an automatic search for attached instruments. If it finds the G3, it will automatically connect. To connect instruments: 1. If the instrument you want to connect with is not listed, ensure it is plugged into an RS-232 port.

  • Page 40: Apply Vacuum

    1. Ensure the vacuum chamber is properly in place, its eight mounting screws secured, and the eight external supports installed and properly tensioned to very light finger tightness only. Document: G3 Manual 4/26/2024 Page 40 of 87...

  • Page 41: Fill, Purge, And Chill

    Low humidity and low flow rates require less water. High humidity and high flow rates require more water and therefore more frequent filling. Filling may only be performed when the saturator temperature is well above freezing (at least 5 °C or higher). Document: G3 Manual 4/26/2024 Page 41 of 87...
  • Page 42 3. If not already enabled, press the Cooling button to turn on saturator temperature control. 4. Ensure the G3 is still in purge mode (the Purge button is pressed in). However, if it is in generate mode, press the Purge button to switch to purge mode.

  • Page 43: Selecting Humidity Control Mode

    This is done while the system is still in Purge mode. 1. Ensure the G3 is still in purge mode (the Purge button is pressed in). However, if it is in generate mode, press the Purge button to switch to purge mode.
  • Page 44 If, however, the saturation temperature setpoint you chose would not allow the G3 to reach your humidity setpoint, a new automatic setpoint will be chosen by the system, over-riding your saturation temperature setpoint. Changing the Saturation Temperature does not change the humidity mode.

  • Page 45: Changing Set Points

    5.4.1. Changing Set Points Setpoints are used to inform the G3 of the desired humidity output, flow rate, and other factors. Setpoints are used as the target values for control.

  • Page 46: Purge Mode

    Once purged, and the saturator temperature is below freezing, the G3 may be switched to Generate mode. The pressure dew point of the gas supplied to the G3 should be lower than the saturation temperature settings while in Purge mode. If the pressure dew point is higher (warmer, wetter) than the saturator temperature, then purging will have the opposite effect of wetting rather than drying the gas path.

  • Page 47: Viewing Data Graphically

    Graph Color Enable/Disable current data plot Figure 4.16 Start a new Click to Add Plot Note, X-Axis manual Minimize Close graph then click within plot to entry scale Graph Graph insert note. Document: G3 Manual 4/26/2024 Page 47 of 87...

  • Page 48: Auto Profiling

    Save profile • Start profile • Pause profile Control pull-down • Stop profile Set point entry Profile Total Time Move set-point line up/down Timer set-point controls for run time at each point Document: G3 Manual 4/26/2024 Page 48 of 87...

  • Page 49: Change Units

    Contact RH Systems, LLC for more information. 5.11.1 Serial connection The G3 is supplied with several RS-232 serial comm ports located on the left side panel. There are several USB ports there also, each of which could support additional comm ports via USB-Serial converters.
  • Page 50 To connect, plug the female end into any of the Plug the male end into the instrument. available serial ports on the left side of the G3. 5.11.2 Software connection After making the physical cable connection, connect to the RHS Control software by pressing the Connect button.

  • Page 51: Data Logging

    Log Configuration allows for changes to the log file data formatting options. It also allows setting the maximum log file size. Once the size is reached, the file will close and a new log file will automatically be generated. Document: G3 Manual 4/26/2024 Page 51 of 87...

  • Page 52: Model G3 Sub-Systems

    6 Model G3 Sub-Systems This section provides details of the functional systems within the G3. These subsystems include the Electrical System, Pneumatic System, and Temperature Control System. Electrical System The G3 requires 100-240 VAC, 50/60 Hz, single phase power. 6.1.1 AC Power AC power enters the system via the power connector located at the back panel, transferring AC into the system via a two-pole 15-amp circuit breaker.
  • Page 53 48 VDC power is enabled, therefore applying 48 VDC to the Stirling cooler circuit boards. The power supply is located on the back side of the MCB control panel. Document: G3 Manual 4/26/2024 Page 53 of 87...

  • Page 54: Embedded Control System

    Main Controller Board The Main Controller Board (MCB) has many different inputs and outputs used to operate the G3. Grouped by functional type, the following tables in this chapter list the various inputs and outputs of the MCB and reference the specific sections of this manual where each input or output is discussed.
  • Page 55 Output B.V2 controls the upper Stirling cooler, while output B.V3 controls the lower stirling cooler. B.V2 and B.V3 each set an output level of 1-5 VDC representing a Stirling cooling power setpoint of 0-100%. Document: G3 Manual 4/26/2024 Page 55 of 87...

  • Page 56: Precision Resistance Measurement Board

    12 VDC power to Temp Board AD4-7 Unused Precision Resistance Measurement Board All temperature sensors in the G3 are 100 Platinum Resistance Thermometers (PRT’s). The following table lists the probe channels and functions of the G3. Channel Probe name Function...

  • Page 57: Stepper Motor Controllers

    Stepper motor controllers control the position of custom linear actuated needle valves used to vary and control flow rate. The stepper controllers STF1 and STF3 control the G3’s Flow1 and Flow3 setpoints (Flow 2 is controlled in a different manner and therefore has no stepper controller). The stepper controllers are individually addressable via an RS-485 communication protocol.
  • Page 58 Power In Warm side Measurement thermistor Warm side Measurement thermistor DC (+) DC (-) 1-5 VDC(+) Input SetPt 0 VDC Enable 0 VDC Input Gnd Stirling Output Drive Output Stirling Output Drive Output Document: G3 Manual 4/26/2024 Page 58 of 87...
  • Page 59 The G3 overcomes this potential problem by allowing the probes internal sheath to remain at atmospheric pressure while physically residing within the vacuum chamber. The probe sheath is sealed to a pressure tube that is vented to the environment outside the vacuum chamber.

  • Page 60: Auxiliary Heaters

    RLY 3. 6.7.2 Flow Controller Heating Depending on the specific G3, heaters may also exist on the flow controller to assist in drying the flow controller’s gas path. Flow controller temperature is an integral measurement of the flow controller itself and is queried along with its other parameters.
  • Page 61 MCB on UART 0_Z. Replies from the pressure controller are received on UART 0_A. Signal ground connection is at UART 0_GND. Typical communication occurs at 19200 baud, 8 data bits, 1 stop bit, no parity. Document: G3 Manual 4/26/2024 Page 61 of 87...
  • Page 62 UART0_GND. Typical communication is at 19200 baud, 8 data bits, 1 stop bit, no parity. Newer G3 systems only use Alicat flow control on Flow 2. Flow 1 and 3 are handled via Stepper valve and flowmeter (see section 6.8.6 Flow Control - Stepper...
  • Page 63 6.8.7 Vent Solenoid For venting the saturator of pressure, and for draining of excess water during filling operations, the G3 is equipped with a vent solenoid. The vent valve is a normally closed solenoid valve. To vent, the solenoid is energized via RLY 11. When de-energized, the vent valve is blocked.
  • Page 64 UART 3 rather than a shared connection on UART2. 6.8.10 External Pressure Sensor There is no dedicated external pressure sensor in the G3. Rather, the low range sensor, P , is used to monitor external (front panel) pressure, time-sharing when needed between the external (front panel) pressure and the saturation pressure.

  • Page 65: Calibration

    10. Using the Reference Pressure and Raw Reading data, compute new calibration coefficients A0, A1, A2, and A3 to the formula P = A0 + A1*Raw + A2*Raw + A3*Raw where P is Reference Pressure Document: G3 Manual 4/26/2024 Page 65 of 87...
  • Page 66 1. Set the Saturator Pressure setpoint to 0 (it will show 10 psia as a minimum but that’s ok). 2. Set all Flow Rate setpoints to 0. 3. Unplug the green connectors at RLY 9 and RLY 10 of the MCB (see section 6.8.8). This pneumatically isolates the pressure transducer. Document: G3 Manual 4/26/2024 Page 66 of 87...
  • Page 67 Value of A0 should be between 0 and ±1 Value of A1 should be between +0.9 and +1.1 Value should be between 0 and ±1E-5 Value should be between 0 and ±1E-9 Document: G3 Manual 4/26/2024 Page 67 of 87...

  • Page 68: Temperature Calibration

    Ro, a, b, and c coefficients. 14. Press the Save Coefficients button to store the new coefficients to the G3 permanent memory. 15. Repeat steps 12 through 14 for each of the remaining probes being calibrated.
  • Page 69 Ro, a, b, and c coefficients. 9. Press the Save Coefficients button to store the new coefficients to the G3 permanent memory. 10. Repeat steps 7 through 9 for each of the remaining probes being calibrated.

  • Page 70: Vacuum Chamber

    2. As the top front panel moves with the vacuum chamber, you’ll need to unsecure it from the G3 frame. To do so, reach up into the front top panel corners and loosen the 2 thumb screws from each side that are securing the top panel to the frame.
  • Page 71 Ensure the pin locks in place with the foot in the downward position. 7. It is now safe to extend the chamber fully outward toward the front. The foot will prevent the G3 from tipping. Retraction of the vacuum chamber is the reverse of extraction.

  • Page 72: Opening Vacuum Chamber

    For example, if the screws are numbered in a circle from 1 to 8, loosen in the following order: 1, 4, 7, 2, 5, 8, 3, 6. Document: G3 Manual 4/26/2024 Page 72 of 87...
  • Page 73 Lift and rock the plate slightly in different areas until acrylic clears bottom plate O-rings. 13. Lift the plate upward to access the inner chamber. Document: G3 Manual 4/26/2024 Page 73 of 87...

  • Page 74: Closing Vacuum Chamber

    (unless you plan to relocate or ship the system). 14. Replace 6 thumbscrews in the lower back panel. 15. Retighten 4 thumbscrews inside upper top panel edges. 16. Replace side panels. 17. Run the system normally. Document: G3 Manual 4/26/2024 Page 74 of 87...

  • Page 75: Parts List

    9 Parts List Document: G3 Manual 4/26/2024 Page 75 of 87...
  • Page 76 Document: G3 Manual 4/26/2024 Page 76 of 87...
  • Page 77 Document: G3 Manual 4/26/2024 Page 77 of 87...
  • Page 78 9 Top Vacuum Flange Part A 10 Top Vacuum Flange Part B 11 Bottom Vacuum Flange 12 Flow-generator & Purge - 3 Way Valve 13 Nitrogen Inlet Pressure Regulator 14 Purge outlet valve 15 Entry On-off Valve Document: G3 Manual 4/26/2024 Page 78 of 87...

  • Page 79: Drawings

    10 Drawings Document: G3 Manual 4/26/2024 Page 79 of 87...
  • Page 80 Blocking valve (1) Exit pressure transmitter (low range) blocking valve (2) Water fill point Water fill pump Water fill tank Vacuum pressure gauge Vacuum pump Vacuum chamber Vacuum chamber over pressure valve Document: G3 Manual 4/26/2024 Page 80 of 87...
  • Page 81 Fig. 8 Document: G3 Manual 4/26/2024 Page 81 of 87...
  • Page 82 Fig. 9 Document: G3 Manual 4/26/2024 Page 82 of 87...
  • Page 83 Fig. 10 Document: G3 Manual 4/26/2024 Page 83 of 87...
  • Page 84 Saturator Temperature Sensor b (lower) Saturator pressure sensor (transmitter) Exit pressure sensor (transmitter) gas inlet pressure sensor Gas inlet valve Directional valve to select gas flow path purge / generate Vent valve solenoid Document: G3 Manual 4/26/2024 Page 84 of 87...
  • Page 85 Flow 2 controller – optional Flow 3 controller – optional Vacuum gauge sensor User Interface with PC – custom programming 24 VDC power supply 48 VDC power supply Power switch with integrated LED indicator Document: G3 Manual 4/26/2024 Page 85 of 87...
  • Page 86 Document: G3 Manual 4/26/2024 Page 86 of 87...
  • Page 87 Summary of Changes Author preliminary 25 Apr 2018 Initial Rev 1 17 Jul 2022 Major revision overall Rev 1.3 23 Jul 2023 Grammar/spelling corrections Rev 1.3.1 26 Apr 2024 Review and minor changes Document: G3 Manual 4/26/2024 Page 87 of 87...

Table of Contents