SAFETY SYSTEMS TECHNOLOGY NOVA-Sensor GIR901 Design Manual

Infrared combustible gas

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D
ESIGN
Model GIR901
Infrared Combustible Gas
NOVA-Sensor
The information in this document is applicable to
sensors built on or after October, 2001
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Summary of Contents for SAFETY SYSTEMS TECHNOLOGY NOVA-Sensor GIR901

  • Page 1 ESIGN ANUAL Model GIR901 Infrared Combustible Gas NOVA-Sensor 7 0 0 4 3 The information in this document is applicable to sensors built on or after October, 2001 T h e i n f o r m a t i o n a n d t e c h n i c a l d a t a d i s c l o s e d b y t h i s d o c u m e n t m a y b e u s e d a n d d i s s e m i n a t e d o n l y f o r t h e p u r p o s e s...
  • Page 3: Table Of Contents

    Quick Finder - Model GIR901 Infrared Combustible Gas NOVA-Sensor QUICK START ......... . 901-1 Apply Power .
  • Page 5: Quick Start

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR QUICK START Apply Power A 30 second countdown is displayed, followed by a brief display of the firmware revision (e.g. “1.18”). Then the decimal points will flash while the unit displays “000” to confirm to the user that the NOVA-Sensor readout unit is properly functioning.
  • Page 6: Description

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR DESCRIPTION The SST Model GIR901 Infrared Combustible Gas NOVA-Sensor is a completely self- contained device that measures and displays the concentration of gas accumulated in a protected area, performs local control functions, and transmits this information to a central control point.
  • Page 7: Detectable Gases

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR Detectable Gases As a rule, most members of the hydrocarbon family are indiscriminately detected by the GIR901. In contrast to the catalytic detector, long-chained hydrocarbons are detected with greater sensitivity than Methane and Ethane. The measuring principle is similarly applicable for other gases that chemically consist of dipole structures, such as CO (with a 4.25 μm filter), and others, but NOT to mono-atomic or bi-atomic elements, such as H...
  • Page 8: Technical Specifications

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR TECHNICAL SPECIFICATIONS Power Supply ... .24 volts DC nominal, 180 mA standby, 240 mA when in alarm. Will operate within specifications at any supply voltage between 16 and 32 volts.
  • Page 9: Installation Sequence

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR Installation Sequence The electronics module contains parts that are delicate and potentially sensitive to electrostatic discharge (ESD). Remove the electronics module and store in the shipping box during installation. Reinstall the module just before system start-up, after all drilling and wiring is completed.
  • Page 10: Wiring

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR Wiring Power input and Analog Signal Output A typical installation is shown in figure 901-2. This setup uses three wires between the NOVA-Sensor and the associated control modules. These wires carry the 24 VDC operating power for the sensor, and transmit the 20 mA signal to the controls.
  • Page 11: Remote Sensor Version

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR the respective terminals for any relays to be used. These are voltage-free “dry” contacts for connection to external equip- ment. Each of the three contacts may be independently set to be normally open or normally closed.
  • Page 12: Dip Switch Settings

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR • If shielded cable is used, it must be grounded only at the GND terminal in the GIR901 electronics enclosure. GIR901 enclosure must also properly grounded. Insulate the shield at the sensor end that will grounded.
  • Page 13: Operation

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR OPERATION Power-Up When power is first applied, the microcontroller executes a built-in test (BIT), during which various internal components and parameters are checked. During the BIT, the indicator lights will be flashing. Upon successful completion of the BIT, the NOVA-Sensor begins a 30 second countdown period to allow time for proper temperature stabilization.
  • Page 14: Calibration

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR Calibration The GIR901 NOVA-Sensor is pre-calibrated at the factory for a specific target gas. It cannot be recalibrated to another hydrocarbon gas unless you replace the transmitter module in the gas sensor head with a new module. See the markings on the outside of the sensor head to determine which gas is required for calibration.
  • Page 15 MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR 4) At this point, only the gas sensor head is being calibrated. During head calibration, the output of the head is held at the “zero” level, so the digital read-out continues to alternate between “CAL” and a small number that represents the zero gas concentration, relative to the previous calibration.
  • Page 16: Recalibration Schedule

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR Recalibration Schedule Due to the extreme stability of the infrared gas sensor, recalibration is rarely required. However, SST recommends that test gas should be applied to the sensors every 90 days to verify proper sensor operation. Before testing, do a visual inspection to check for contamination of the sintered metal sensor cover, loose parts, etc.
  • Page 17: Final Operational Check-Out (Comptest™)

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR Figure 901-5 Relay Contact Protection Scheme FINAL OPERATIONAL CHECK-OUT (CompTest™) Once the NOVA-Sensor has entered normal operation, a final comprehensive output test (CompTest) of all detector inputs and outputs is available. The CompTest is a way to verify that the NOVA-Sensor relay outputs and 0 to 20 mA current loop are correctly operating.
  • Page 18: Entering The Safety-Code

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR The CompTest must be started within 6 minutes of entering Protection Mode. The Safety-Code™ is entered into the NOVA-Sensor by using the remote Reset button, not the MODE switch which is on the NOVA-Sensor housing. You begin the test in either of the two ways described below.
  • Page 19: Maintenance

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR Fault Test The following outputs are simultaneously toggled three (3) times, and are held in each state for approximately 2 seconds. 0 to 20 mA Loop Alternates between 0 and 4 mA Fault Relay Toggles between Fault and no fault LOW alarm relay Inactive...
  • Page 20: Digital Readout Module Replacement

    MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR 2) Remove the sintered metal cover from the sensor head by loosening the set screw and then turning the cover counter-clockwise. 3) The infrared source lamp is contained inside the plug-in gas detection element visible on the PC board assembly.
  • Page 21 MODEL GIR901 INFRARED COMBUSTIBLE GAS NOVA-SENSOR 3) If an electronics module that is not calibrated or that had been calibrated with a different sensor (in a different enclosure) is plugged into an enclosure, positive or negative gas values may be displayed. In this case, make sure that alarming devices are disconnected before plugging in, and that the unit is calibrated before re-connecting the alarming devices.
  • Page 22 Blank Page...

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