Digital magnetometer CTM-6W

Overview
The CTM-6W is a portable single-axis fluxgate magnetometer for measuring weak DC magnetic fields. Typical uses include testing magnetic shielding devices, field values from measurement coils, residual magnetization of materials, and direct measurement of Earth's magnetic field components with six-digit resolution. The instrument can output data via an RS-232 interface and is designed for straightforward field operation and calibration use.

Main performance indicators of CTM-6W fluxgate meter

• Measurement range: ± 99999.9 nT (1 Gs)
• Resolution: 0.1 nT (six-digit display)
• Static noise: < 0.2 nT (p-p)
• Residual magnetic bias: < 10 nT
• Accuracy: 0.05% ± 10 nT
• Display: LED, six-digit
• Output: RS232 with optical isolation, ASCII
• Zero compensation: front-panel Zero key (sets any point in full range to zero)
• Warm-up time: 15 min
• Power supply: internal 12 V lithium battery or external charger
• Probe dimensions: Φ8 mm × 50 mm; Chassis: 130 × 170 × 55 mm
• Battery life: ~15 hours continuous

Instructions and operation

• Insert the probe into the front-panel probe socket and switch on the instrument (rear panel). The display shows the probe axial magnetic field (e.g., H-98765.4 nT; a leading “-” indicates opposite direction).
• Press the Zero button to set the display to P 00000.0 — this offsets the reading to zero to measure small changes relative to a base value. Press again to cancel.
• RS232 interface (rear panel): 9-pin standard connector; communication: 8-bit asynchronous, 8 data bits, no parity, 1 stop bit; baud rate 19200; ASCII output. Send character 's' to start transmission and 'q' to stop.
• Internal battery provides ~15 hours continuous operation. When depleted the display will turn off. The supplied charger plugs into the rear socket to charge the battery and can power the instrument while charging (even when instrument is off).

Application example
To measure the weak axial field inside a magnetic shielding tube with a single-component fluxgate: place the probe axis coincident with the tube axis and record reading B1; rotate the probe 180° and record reading B2 (including sign). The tube field = (B1 - B2) / 2. The instrument zero (residual) = (B1 + B2) / 2.

Precautions

• Handle probe and chassis carefully; avoid squeezing, impacts or drops.
• Keep the probe away from strong magnetic fields to prevent magnetization.
• The probe and chassis are a matched set and must be used together.
• Use only the dedicated charger supplied with the instrument.
• To preserve battery life, recharge at least once a month if unused.

Technical specifications

• Model: CTM-6W (portable fluxgate magnetometer)
• Measurement range: ± 99999.9 nT (1 Gs)
• Resolution: 0.1 nT (six-digit display)
• Static noise: < 0.2 nT (p-p)
• Residual magnetic bias: < 10 nT
• Accuracy: 0.05% ± 10 nT
• Display: LED, six-digit
• Output: RS232 with optical isolation, ASCII
• Serial parameters: 19200 baud, 8 data bits, no parity, 1 stop bit
• Zero compensation: front-panel Zero key
• Warm-up time: 15 minutes
• Power supply: internal 12 V lithium battery or external charger; charger can power instrument and charge battery when instrument is off
• Battery life: ~15 hours continuous
• Probe dimensions: Φ8 mm × 50 mm
• Chassis dimensions: 130 × 170 × 55 mm