company profile news email HTI links
MODEL M520
HELIUM LEVEL MEASUREMENT
CAMAC MODULE
 
  • Connects directly to six superconductive-wire liquid helium level probes
  • Programmable probe excitation current and zero/span factors allow optimization of probe operating point
  • Powered entirely from the CAMAC dataway--no external equipment required for level measurement
  • Fully conditioned level data is available in transparent dual-port memory for rapid computer access
  • Probe protection features reduce the likelihood of probe damage caused by operation in abnormal conditions
The Highland model M520 is a self-contained, single-width CAMAC (IEEE-583) module which is capable of measuring six liquid helium levels when interfaced to standard superconductive-wire type level sensors. The module incorporates an internal microprocessor which supervises probe scanning and level computation.

The M520 incorporates features which allow probe operating current to be optimized to the liquid helium temperature, allowing reliable level measurements from 5.0 to 1.5 Kelvins. Individual probe operating points are written to the module from the CAMAC dataway, based on externally measured temperatures acquired by the Highland M460 or other devices.

Probe protection features include full current limiting, provision for deleting any or all probes from scanning, and fast-response shutdown of probe current upon probe over-voltage, as might occur if probes are operated in vacuum.
MODEL M520 HELIUM LEVEL MEASUREMENT CAMAC MODULE
  CONFORMANCE Meets all mandatory requirements of IEEE-583-1982 CAMAC specifications.
  PACKAGING  Single-width CAMAC module.
  SENSORS
Compatible with most superconductive-wire, 4-lead level probes, such as those manufactured by AMI and others.
  PROBE POWER Probe constant-current source is programmable from 0 to 128 mA; compliance range is 0 to 42 volts with full overload and wiring fault protection. Current source is accurate to .1% FS.
  VOLTAGE INPUT Probe voltage drop from 0 to 25 volts is measured and digitized to 0.1% accuracy. Consult factory for larger probe voltages.
CAMAC ADDRESS/FUNCTION CODES
 
 A(n)  F(0)
 A(n+6)  F(0)
 A(n+6)  F(16)
 A(12)  F(0)
 A(13)  F(0)
 A(13)  F(16)
 A(14)  F(0)
 A(15)  F(0)
 A(n)  F(1)
 A(6)  F(1)
 A(7)  F(1)
 A(13)  F(1)
 A(14)  F(1)
 A(15)  F(1)
Read level, probe n, n=0 to 5
Read probe parameter word, probe n
Write probe parameter word, probe n
Read module status
Read delay between scans
Write delay between scans
Read delay between scans counter
Read scan counter
Read probe raw data
Read current source check raw data
Read ADC diff. amp. offset voltage
Read program I.D.
Read program revision
Read module I.D
Highland Technology Model M520 Helium Level Measurement CAMAC Module Data Sheet