Siglent SDM3045X Digital Multimeter: Specs and Buying Checks

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The Siglent SDM3045X is a 4½-digit benchtop digital multimeter with a dual display and True-RMS AC measurement. Its datasheet is not consistent about its count figure: one line gives 60,000 counts and another gives 66,000 counts. Its user manual rates the input for IEC Measurement Category II at up to 300 VAC, which is lower than the SDM3055’s 600 VAC rating. This guide sets out those statements and what to check before you buy the SDM3045X.

Quick answer

The datasheet describes the SDM3045X as a 4½-digit multimeter, but gives 60,000 counts in one place and 66,000 counts in another.
The datasheet lists DC voltage from 600 mV to 1000 V and True-RMS AC voltage from 600 mV to 750 V.
The user manual states IEC Measurement Category II with inputs up to 300 VAC, a lower rating than the SDM3055’s 600 VAC.
Standard interfaces are USB Device, USB Host and LAN. USB-GPIB is an optional accessory.
Check the Category II (300 V) rating and the fuse ratings before you connect it to any circuit.

The count figure is inconsistent

The datasheet’s product overview describes the SDM3045X as a 4½-digit digital multimeter with 60,000 counts. Its main-features section describes “real 4½ digit” readings with 66,000 counts. Both figures appear in the same document. We cannot tell from the datasheet which one applies, so this article does not pick one. If the count figure matters for your purchase, check the user manual and ask the manufacturer to confirm it before you rely on it.

The count figure is a resolution figure, not an accuracy figure. Accuracy is stated separately for each function and range. The datasheet gives the accuracy tables for DC voltage, AC voltage, DC current, AC current, resistance, capacitance, frequency and temperature.

What the SDM3045X measures

The datasheet lists the basic measurement functions as DC voltage, DC current, True-RMS AC voltage, True-RMS AC current, two-wire and four-wire resistance, capacitance, continuity, diode test, frequency, period, and temperature for thermocouple and RTD sensors. Its math functions include maximum, minimum, average, standard deviation, dBm and dB, relative measurement, pass/fail, histogram and trend chart.

The datasheet’s stated ranges start higher than the SDM3055’s in several places. DC voltage starts at 600 mV, and True-RMS AC voltage starts at 600 mV. True-RMS AC current starts at 60 mA and runs to 10 A. Frequency measurement runs from 20 Hz to 500 kHz, which is lower than the 1 MHz upper limit the SDM3055 datasheet gives. Check the ranges you need before you buy, because a meter that starts at a higher range may not cover your smallest readings.

Speed and display

The datasheet states a measurement speed of up to 150 readings per second. It does not give a rate for each function or range, so do not assume that rate applies to every measurement. The datasheet also describes a 4.3-inch TFT-LCD at 480 by 272, dual-display operation, a built-in help system, a Chinese and English menu, and file management using a USB drive or local storage.

Safety rating: what the manual states

The user manual lists the SDM3045X under IEC Measurement Category II, with the HI and LO inputs connected to mains under Category II conditions. The manual’s safety-term table gives CAT II as IEC Measurement Category II with inputs that may be connected to mains up to 300 VAC under Category II overvoltage. The manual’s HI-LO protection limit is stated as 1000 VDC or 750 VAC, which is the maximum measurable voltage. The manual’s CAT I entry states 1000 V peak.

Read the 300 VAC figure carefully. It is the Category II limit for mains connections. It is lower than the SDM3055 manual’s 600 VAC Category II figure. If your work involves outlet-level mains, check the rating on the exact model you are buying, because the two Siglent models do not share the same mains rating.

The manual’s category text also says Category II covers devices connected to mains at an outlet on a branch circuit, such as small appliances and test equipment. It warns that permanently installed devices such as main breaker panels and sub-panel boxes are outside that category. Work on those circuits belongs to a licensed electrician, using equipment rated for the location.

Fuses and input protection

The datasheet lists a rear-panel accessible 10 A, 250 V fast-melt fuse and an internal 12 A, 250 V slow-melt fuse. The manual repeats these protections. Replace a blown fuse only with the type and rating the manual specifies. If you cannot identify the fuse in the meter, stop and check the manual before you measure again.

Interfaces and remote control

The datasheet lists USB Device, USB Host and LAN as the standard interfaces. The USB-GPIB adapter is an optional accessory. The datasheet says USB and LAN remote interfaces support a common SCPI command set and that the meter is compatible with other popular DMMs. It also lists the EasyDMM PC software. If you need GPIB without an adapter, this model does not include it.

How we chose the sources

This article uses three Siglent documents: the SDM3045X datasheet (EN_04A), the SDM3045x user manual (UM06034-E01A), and the Siglent all-products selection guide dated April 2026. We opened each one on 2026-10-27 and confirmed its text can be read. We quote only figures and statements that appear in those documents. We did not use retailers, resellers or third-party manual archives for any specification in this article.

Who the SDM3045X suits

The datasheet lists research and development laboratories, detection and maintenance, calibration laboratories, and automatic production test among the application fields. It fits bench work where you need dual display, True-RMS AC and remote control, and where the mains rating in the manual is sufficient for the circuits you will measure.

It is not a handheld tool for field electrical work, and it is not the right choice for permanently installed mains equipment. For a handheld meter, choose one with a CAT rating that matches the circuit and read our guide to the functions and types of digital multimeters before you decide.

Comparing the SDM3045X with the SDM3055

Both Siglent models use True-RMS AC, dual display, USB and LAN, and the same fuse protections in their datasheets. The main differences in the documents are the digit count, the stated ranges, and the Category II voltage. The SDM3045X datasheet gives 4½ digits and a 300 VAC Category II limit in its manual. The SDM3055 datasheet gives 5½ digits and its manual gives a 600 VAC Category II limit. The selection guide lists both models in separate sections. If the 300 VAC limit is too low for your circuits, the SDM3055 is the model to check. For another bench meter to compare against, see our guide to the Keysight 34461A.

Buying checklist

Confirm the functions and ranges you need appear in the datasheet, starting at 600 mV for voltage.
Resolve the count figure with Siglent before you rely on it. The datasheet gives both 60,000 and 66,000 counts.
Check the Category II rating in the manual and compare it with the highest mains voltage you will measure.
Confirm the fuse ratings and keep the manual’s replacement instructions with the meter.
Decide whether you need LAN or USB remote control, and whether you need the USB-GPIB adapter.

Mistakes to avoid

Do not treat the count figure as an accuracy claim. Accuracy depends on the function, the range and the tolerance tables.
Do not assume the SDM3045X has the same 600 VAC mains rating as the SDM3055. The manual states 300 VAC for Category II.
Do not use the meter on permanently installed mains equipment. The manual says those circuits are outside the Category II limits.
Do not assume GPIB is included. The datasheet lists it as an optional adapter.

FAQ

Is the SDM3045X a 4½-digit or 5½-digit meter?

The datasheet describes it as a 4½-digit multimeter. Its count figure is given as 60,000 in one place and 66,000 in another, so resolve that with Siglent before you rely on either number.

What is the SDM3045X’s CAT rating?

The user manual states IEC Measurement Category II with inputs up to 300 VAC, and it lists CAT I at 1000 V peak. Check the manual for the exact conditions before you connect the meter to a circuit.

Does the SDM3045X measure True-RMS AC?

Yes. The datasheet lists True-RMS AC voltage from 600 mV to 750 V and True-RMS AC current from 60 mA to 10 A.

Which interfaces does it have?

The datasheet lists USB Device, USB Host and LAN as standard. USB-GPIB is an optional accessory.

How does it compare with the SDM3055?

The documents differ in digit count, starting ranges and the Category II voltage. The SDM3045X manual states 300 VAC for Category II, while the SDM3055 manual states 600 VAC.

What we could not verify

The sources we opened do not give a price, a shipping time or current availability, and this article does not state them. We could not confirm which of the two count figures is correct, so this article quotes both. The datasheet’s accuracy tables are long, so this article quotes the function list and headline figures only. For a purchase decision, read the accuracy table for each function and range you need.

Bottom line

The Siglent SDM3045X is a benchtop multimeter with True-RMS AC, dual display and USB and LAN remote control. Its manual rates it for Category II at up to 300 VAC. Buy it for bench and laboratory work that stays within those ratings. For higher mains voltages or for panel and service work, choose a different model or a tool with the right rating, and leave panel work to a licensed electrician.

Sources

Siglent, SDM3045X Digital Multimeter Datasheet, EN_04A, https://siglentna.com/download/2587 (opened 2026-10-27)
Siglent, SDM3045x User Manual, UM06034-E01A, https://shop-us.siglent.com/wp-content/uploads/2025/11/SDM3045x_UserManual_UM06034-E01A.pdf (opened 2026-10-27)
Siglent, All Products Selection Guide, April 2026, https://shop-us.siglent.com/wp-content/uploads/2026/06/Siglent-all-products-selection-guide-2026-04.pdf (opened 2026-10-27)