Gamma Modulator FHG65

Summary

Gamma Modulator FHG65

The Gamma Modulator FHG65 is designed to improve measurement accuracy in radiometric systems by effectively suppressing background and extraneous radiation. It achieves this by using a rotating shaft that alternately screens and allows the useful beam to pass at a frequency of 1 Hz, differentiating it from ambient interference. This allows instruments like the Gammapilot FMG50 or FMG60 to separate the useful signal using a frequency filter, thereby increasing measurement certainty and system availability.

Application

• Suppression of background and extraneous radiation for radiometric measurements.

Advantages

• Disturbance-free measurement even with interference radiation and variable background radiation.
• Simple mounting and integration into existing systems.
• Maintenance-free operation.

Technical Data

Power Supply

• Supply voltage: 18 to 36 VDC
• Power consumption: 3.2 W
• Overvoltage category: II
• Protection class: 1
• Potential equalization: Provided

Environment

• Ambient temperature:
  • Without water cooling: –40 to +60 °C (–40 to +140 °F)
  • With water cooling at the water cooling jacket: 0 to +120 °C (32 to +248 °F)
  • With water cooling at the terminal head: max. +75 °C (+167 °F)
• Storage temperature: –40 to +75 °C (–40 to +167 °F)
• Housing degree of protection: IP66/67; TYPE 4X/6
• Climate class: DIN EN 60721-3-3 (test Z/AD)
• Vibration resistance: DIN EN 60068-2-64 (test Fh; 10 to 2000 Hz, 1 (m/s²)²/Hz)
• Shock resistance: DIN EN 60068-2-27 (test Ea; 30 g, 18 ms, 3 shocks /direction/axis)
• Electromagnetic compatibility: Interference emission according to EN 61326 (Industrial) and NAMUR Recommendation NE21.

Interference Suppression

• FMG50:
  • Measuring range 200 mm: 25 µSv/h max. interference suppression
  • Measuring range 800 mm: 6 µSv/h max. interference suppression
  • Measuring range 2,000 mm: 2.5 µSv/h max. interference suppression
  • Measuring range 10,000 mm (cascading): 0.5 µSv/h max. interference suppression
• FMG60:
  • Measuring range 200 mm: 50 µSv/h max. interference suppression
  • Measuring range 800 mm: 12.5 µSv/h max. interference suppression
  • Measuring range 2,000 mm: 5 µSv/h max. interference suppression
  • Measuring range 10,000 mm (cascading): 1 µSv/h max. interference suppression

Electrical Connection

• Supply voltage terminals (L+, L-): 18 to 36 VDC
• Synchronization connection terminals (SYNC+, SYNC-): 12 VDC, 5 mA
• Cable requirements: Minimum diameter of 0.5 mm² (20 AWG).
• Available cable entry versions: M20 gland, M20 thread, G ½ thread, NPT ½ thread.

Installation Requirements

• Mounting: Directly on the mounting flange of source containers FQG61 or FQG62. Correct orientation is crucial.
• Fastening: Minimum 4 M16 threaded bolts.
  • Steel torque: 210 Nm (154.88 lbf ft)
  • Stainless steel torque: 144 Nm (106.20 lbf ft)
• Beam path: The modulator reduces the useful horizontal beam angle from 6° to approx. 2°. Ensure the detector is fully covered.
• Water Cooling (for specific versions):
  • Materials: 316L and 304
  • Water connection: 2 x G 1/4"A, DIN ISO 228
  • Outlet temperature: max. +40 °C (104 °F)
  • Water pressure: 4 to 6 bar (58 to 87 psi)
  • Water flow: min. 60 l/h

Mechanical Construction

• Weight without water cooling jacket: max. 18 kg (39.69 lb)
• Weight with water cooling jacket (empty): max. 21 kg (46.31 lb)
• Weight with water cooling jacket (full): max. 25 kg (55.13 lb)
• Operating life of bearings: 36 years (at maximum load, continuous operation).

Materials

• Housing: 304 (1.4301)
• Water cooling jacket: 316L (1.4404)
• Seals (O-ring): FKM 70
• Cable entry materials vary depending on the option (M20 gland, M20 thread, G 1/2 thread, NPT 1/2 thread).

Synchronizer FHG66

The Synchronizer FHG66 is used to synchronize multiple Gamma Modulators FHG65 in a measuring point, ensuring they operate in common mode. It also provides diagnostic capabilities for the connected modulators. A single FHG66 can synchronize up to three FHG65 units, and multiple synchronizers can be cascaded for larger systems.

Technical Data

Input

• Cascading input for connection to another Synchronizer FHG66.
• Galvanically isolated.
• Signal transmission: Closed current loop 0 to 5 mA, max. 12 V.
• Cable requirements: Max. capacitance 120 nF, max. resistance 1000 Ω, max. inductance 0.65 mH.

Output (Alarm Relay)

• Type: Potential-free change-over contact.
• Switching capacity (DC): max. 40 V, max. 2 A, max. 80 W.
• Switching capacity (AC): max. 250 V, max. 2 A, max. 500 VA (at cos φ ≥ 0.7).
• Operating life: Min. 10⁵ switching cycles at maximum contact load.
• Protection class: 2 (double/reinforced isolation).

Power Supply

• Supply voltage: 18 to 35 VDC (requires power supply with safe isolation).
• Power consumption: max. 1 W.
• Overvoltage category: II.
• Pollution degree: 2.

Environment

• Ambient temperature:
  • Mounted individually: –20 to +60 °C (–4 to +140 °F)
  • Mounted in a row without lateral spacing: –20 to +50 °C (–4 to +122 °F)
  • Installed in protective housing: –20 to +40 °C (–4 to +104 °F)
• Storage temperature: –20 to +85 °C (–4 to +185 °F).
• Degree of protection: IP20.
• Mechanical degree of protection: IK06 (1J) according to IEC 62262.
• Electromagnetic compatibility: Class B equipment (interference emission), meets EN 61326 Appendix A (Industrial) and NAMUR NE 21 (interference immunity).

Electrical Connection

• Terminals: Plug-in screw terminals.
• Wire cross-section:
  • Power supply and relay: 1.0 to 2.5 mm² (17 to 13 AWG).
  • Signal lines: 0.5 to 2.5 mm² (20 to 13 AWG).
• Power supply terminals (L+, L-): 18 to 35 VDC.
• Synchronization output terminals (SYNC 1, 2, 3): 12 V / 5 mA.
• Cascading input terminals (CASC_IN): 12 V / 5 mA.

Installation Requirements

• Mounting location: Inside a cabinet outside the hazardous area, protected against mechanical influences. If mounted outdoors, a protective housing (min. IP65) is required.
• Installation: Can be mounted on a DIN rail.

Mechanical Construction

• Weight: approx. 150 g (5.29 oz).
• Housing materials: Polycarbonate, Polyamide PA6.

Human Interface

• Display elements: LEDs for operation (green), general error (red), and error identification (yellow LEDs A, B).
• Operating elements: DIP switches located behind the front panel for enabling/disabling synchronization outputs and the cascading input.

Certificates and Approvals

• CE mark.
• Explosion protection information is available in the full datasheet.
• CSA GP approval.
• Overfill protection: Suitable for max point level detection in SIL 2/3 applications with Gammapilot M FMG60 (200/400 mm) according to IEC 61508. Not tested for WHG overfill protection.

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Disclaimer: This extraction may miss figures, footnotes, or revisions. Contractual data must match the OEM PDF revision used on the project.

Official datasheet (PDF)

Lenntech datasheet mirror