General measurement
Input type: Single Hall effect sensor
Maximum update rate: 30 rdg/s
Probe features: Linearity compensation, probe zero, and hot swap
Measurement features: Autorange, max hold, relative mode, and filter
Probe connector: 15-pin D-sub socket
DC measurement
| Probe type ranges | Filter on 4¾-digit resolution | Filter off 3¾-digit resolution |
| HST probe |
| 350 kG | 000.01 kG | 000.1 kG |
| 35 kG | 00.001 kG | 00.01 kG |
| 3.5 kG | 0.0001 kG | 0.001 kG |
| 350 G | 000.02 G | 000.1 G |
| HSE probe |
| 35 kG | 00.001 kG | 00.01 kG |
| 3.5 kG | 0.0001 kG | 0.001 kG |
| 350 G | 000.01 G | 000.1 G |
| 35 G | 00.001 G | 00.01 G |
| UHS probe (discontinued) |
| 35 G | 00.001 G | 00.01 G |
| 3.5 G | 0.0001 G | 0.001 G |
| 350 mG | 000.02 mG | 000.1 mG |
Measurement resolution (RMS noise floor): Indicated by value in above table for shorted input
Display resolution: Indicated by number of digits in above table
DC accuracy: ±0.20% of reading ±0.05% of range
DC temperature coefficient: -0.01% of reading -0.003% of range/°C
DC filter: 16-point moving average
AC measurement
| Probe type ranges | 3¾-digit resolution |
| HST probe |
| 350 kG | 000.1 kG |
| 35 kG | 00.01 kG |
| 3.5 kG | 0.001 kG |
| 350 G | 000.1 G |
| HSE probe |
| 35 kG | 00.01 kG |
| 3.5 kG | 0.001 kG |
| 350 G | 000.1 G |
| 35 G | 00.01 G |
| UHS probe (discontinued) |
| 35 G | 00.01 G |
| 3.5 G | 0.001 G |
| 350 mG | 000.1 mG |
Measurement resolution (RMS noise floor): Indicated by value in above table, measured at mid-scale range
Display resolution: Indicated by number of digits in above table
| | Narrow-band mode | Wide-band mode |
| AC accuracy | ±2% of reading, ±0.05% of range (20 Hz to 100 Hz); ±2.5% of reading, ±0.05% of range (10 Hz to 400 Hz) | ±2% of reading, ±0.05% of range (50 Hz to 10 kHz) |
| AC frequency response | 10 Hz to 400 Hz | 50 Hz to 10 kHz |
| Minimum input signal | >1% of range | >1% of range, except >2% of range on lowest range |
AC specifications based on sine wave inputs or signals with crest factors <4.
AC temperature coefficient: ±0.01% of reading ±0.006% of range/°C
Front panel
Display type: 2-line × 20-character LCD display module with 5.5 mm high characters and LED backlight
Display units: gauss (G), tesla (T), oersted (Oe), and ampere per meter (A/m)
Display update rate: 3 rdg/s
Display resolution: To ±4¾ digits
Units multipliers: µ, m, k, M
Display annunciators : DC, RMS, max, alarm
Keypad: 14-key membrane
Front panel features: Display contrast control and keypad lock-out
Interfaces
USB
Function: Emulates a standard RS-232 serial port
Baud rate: 57,600
Connector: B-type USB connector
Reading rate: To 30 rdg/s
Software support: LabVIEW™ driver
Alarm
Settings: High setpoint, low setpoint, inside or outside, algebraic or magnitude, audible on/off, and sort
Actuators: Display annunciator, sort message, beeper, and relay
Relays
Number: 1
Contacts: Normally open (NO), normally closed (NC), and common (C)
Contact rating: 30 VDC at 2 A
Operation: Follows alarm or operated manually
Connector: Shared 25-pin D-sub socket
Monitor output
Configuration: Real-time analog voltage output proportional to measured field
Range: ±3.5 V
Scale: ±3.5 V = ±full scale on selected range
Frequency response: DC to 10 kHz
Accuracy: Offset and single point gain corrected to ±0.5% of reading ±0.1% of range; linearity is probe-dependent
Minimum load resistance: 1 kΩ (short circuit protected)
Connector: Shared 25-pin D-sub socket
General
The Model 425 is the replacement for the Model 421 with a new software command set.
Ambient temperature: 15 to 35 °C at rated accuracy, 5 to 40 °C with reduced accuracy
Ambient field: Up to 100 G DC, measured at the instrument chassis
Power requirement: 100 to 240 VAC, 50 to 60 Hz, 40 VA
Size: 216 mm W × 89 mm H × 318 mm D (8.5 in × 3.5 in × 12.5 in), half rack
Weight: 2.1 kg (4.6 lb)
Approval: CE mark, RoHS
Probes and extensions
Probe compatibility: Full line of standard and custom probes (compatible with Model 425/455/475 probes)
Hall sensor compatibility: Front panel programmable sensitivity and serial number for user-supplied Hall sensor using HMCBL cable
Extension cable compatibility: Probe extension cables with an EEPROM are available from 10 ft to 100 ft