YDYT9800 integrated eddy-current sensor

YDYT9800 integrates the probe and driver in one non-contact eddy-current sensor. A molded PPS head seals the coil; the electronics are encapsulated in a stainless-steel threaded body. The signal cable is shielded, with optional stainless-steel armor. Supply-polarity and output-short-circuit protection are described.

The sensor uses a three-wire voltage or current output. Standard calibration uses No. 45 steel unless another target material is specified. Target material and geometry affect the calibration and must match the application.

Operating temperature is −40 to +85 °C, temperature drift is 0.05%/°C and protection is IP68. Frequency response is 0–10 kHz; amplitude attenuation is less than 1% through 1 kHz and less than 5% at 10 kHz. The source's phase text states less than −10° through 1 kHz and less than −100° at 10 kHz; these signed limits are retained as source wording and are not converted into a different acceptance criterion.

Supply	Output alternatives stated
+12 to +30 V DC	0.1–10.5 V in specification, 1–5 V, or 0.5–4.5 V
−18 to −24 V DC	−2 to −18 V
±12 to ±15 V DC	0–5 V, 0–10 V, −5 to +5 V, or −10 to +10 V
+18 to +30 V DC	4–20 mA

The voltage-output consumption is at most 12 mA excluding output current, with ±12 mA printed for the bipolar supply. At a fixed gap, ripple is at most 20 mV peak-to-peak for voltage output or 30 µA for current output. Voltage-output impedance is at most 51 Ω with a maximum stated signal-cable length of 300 m. The current-output load is at most 750 Ω; the stated output change at maximum load is −1%. Confirm the B01 discrepancy before selecting the first positive-voltage output.

Probe diameter	Standard linear range	Extended range listed	Nonlinearity	Minimum target diameter
5 mm	1 mm	2 mm	Within ±1%	15 mm
8 mm	2 mm	4 mm	Within ±1%	25 mm
11 mm	4 mm	8 mm	Within ±1%	35 mm
18 mm	8 mm	12 mm	Within ±1%	45 mm
25 mm	12 mm	22 mm	Within ±1.5%	50 mm
50 mm	25 mm	30 mm	Within ±2%	100 mm

Minimum threaded-body length depends on diameter, thread and armor. M10 × 1 and M14 × 1.5 entries use 75 mm unarmored / 85 mm armored; the listed M12 × 1, M16 × 1 and M30 × 2 entries use 50 / 60 mm where offered. Probe-section lengths are 5–8 mm for a 5 mm probe, 11–13 mm for 8/11 mm probes, 35 mm for 25 mm and 55 mm for 50 mm. The 18 mm probe is in the range table but has no corresponding dimensional entry. Confirm the full selected drawing rather than applying every thread to every probe diameter.

For a cylindrical shaft with the probe axis perpendicular to its centerline, the manual calls for a shaft diameter more than three times the probe diameter. It notes reduced sensitivity on smaller targets, approaching about 70% when target size equals probe-head diameter.

Target thickness should exceed 0.1 mm for ferromagnetic steel or 0.6 mm for weakly magnetic materials such as copper and aluminum. The monitored surface should have no scratches, holes, steps or grooves except deliberate speed/keyphasor features. Stated roughness is 0.4–0.8 µm for vibration and generally no more than 0.8–1.6 µm for displacement.

Probe diameter	Parallel-probe distance Dpx	Orthogonal probes, round target Dcy	Orthogonal probes, square target Dcf
5 or 8 mm	40.6 mm	35.6 mm	22.9 mm
11 mm	80 mm	70 mm	40 mm
25 mm	150 mm	120 mm	80 mm
50 mm	200 mm	180 mm	150 mm

These are the source's diagram-specific spacing dimensions, not interchangeable edge gaps. Confirm their reference points on the configuration drawing. The plastic head must project completely beyond the mounting face, or the mounting face requires suitable relief. Use a rigid bracket with resonance at least ten times rotational frequency.

Choose a linear range more than 15% greater than the total required gap change. For vibration, set the gap at the linear midpoint. For displacement moving mainly away from the probe, start near the near end of the linear range; for movement mainly toward the probe, start near its far end.

Use output to adjust the gap, but make sure the head is beyond the mounting hole. The source describes high saturation before insertion, lower output inside the hole, a high output as the head emerges far from the target, then the correct gap output as the probe approaches the actual surface. A correct-looking reading inside the hole may be caused by surrounding mounting metal.

Recalibrate after more than a year unused or more than two years of continuous operation. Some units have a small potentiometer at the rear for linearity/sensitivity calibration. The source recommends the YD-20 static displacement calibrator and sealing the potentiometer with silicone after calibration. This adjustment is not documented for every unit and no universal trim direction or step size is supplied.

The printed formula is YDYT9800-A-B-C-D-E-F. A examples are 01 = 0–1 mm, 02 = 0–2 mm and 03 = 0–4 mm.

B01 is printed as 0.5–10.5 V, conflicting with the specification. Other listed B codes are 02 = 1–5 V, 03 = 4–20 mA, 04 = −2 to −18 V, 05 = 0–5 V, 06 = −5 to +5 V and 07 = −10 to +10 V. The specification includes additional output possibilities that have no code in this list.

C01–C06 are M10 × 1, M16 × 1, M12 × 1, M14 × 1.5, M30 × 2 and custom. D01 is an 80 mm body, D02 120 mm and D03 custom. E01/E02/E03 are 1/2/3 m cable examples. F is undefined. Confirm a complete order description directly; do not borrow a missing field from YDYT9810.