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Keithley 2750 Multimeter/Switch System: Specs and Checks

Quick answer: The Keithley 2750 is a five-slot mainframe that combines a 6½-digit, 14-function digital multimeter with switching for up to 200 channels of two-pole switching. Its datasheet describes the built-in DMM as a true 6½-digit, 22-bit instrument. The user’s manual states the 2750 is Installation Category I and must not be connected to mains, so it is a rack and test-system instrument, not a meter for an electrical panel or outlet.

Quick answer

• Type: 6½-digit DMM plus a five-slot switching and data acquisition mainframe, from Keithley Instruments (now part of Tektronix).
• Stated resolution: true 6½-digit (22-bit) resolution, per the datasheet.
• Stated switching: up to 200 channels of two-pole switching, with 300 V isolation on channels, using plug-in switch and control modules.
• Stated category: Installation Category I. The manual says the 2750 must not be connected to mains.
• Check before buying: which switch modules you need, the voltage limit each module allows, and whether your work is on a bench or in a rack.

What the 2750 is

The 2750 user’s manual describes it as a 6½-digit high-performance multimeter and data acquisition system. The datasheet puts it more plainly: a five-slot mainframe that combines a 6½-digit, 14-function DMM with support for up to 200 channels of two-pole switching and multi-channel analog and digital I/O control. In other words, the meter is one part of the unit. The mainframe takes switching and control modules, and the DMM measures whichever channel you connect to it.

The datasheet lists the measurement functions the 2750 handles, including voltage, current, resistance, temperature, frequency, and continuity. If your work is a single meter for a bench, a handheld multimeter or a benchtop DMM without switching is a better match than this system.

Resolution and speed

The datasheet describes true 6½-digit (22-bit) resolution. It also says the mainframe can scan and measure more than 200 channels per second. That figure applies to the switching system as a whole, so check it against the module and measurement you plan to run before you use it in a test sequence.

The manual’s digits chapter explains the digits setting and how to set it remotely. Pick the digits and integration time for your measurement first, then check the speed for that setting in the manual. Do not treat the channel rate as the DMM’s reading rate.

Switching channels and module limits

Channels are where the 2750 differs from a standard meter. The datasheet says it supports up to 200 differential input channels with 300 V isolation, and it lists twelve optional plug-in switch and control modules, with more in development. Up to five modules can be mixed to combine switching and control on one mainframe.

Each module has its own limits, and the user’s manual gives them in a table for the 7700-series modules. For example, the table lists the 7700 with 20 channels of two-pole operation and a 300 V maximum for measuring volts. The 7701 is listed with 32 channels and a 150 V maximum for measuring volts. The 7702, 7703, and 7705 are also listed with a 300 V maximum for measuring volts. Check the table for the exact module you buy, because the limit changes by module.

The manual also includes a note on which channels can measure amps. It says the amps capability depends on the module and the channel. Read the amps row for your module before you connect any current source.

Safety category: read this before you connect anything

The user’s manual says Keithley products are designed for use with signals rated Installation Category I and Installation Category II, as described in IEC 60664. It then says most measurement, control, and data I/O signals are Installation Category I and must not be directly connected to mains voltage or to voltage sources with high transient overvoltages. The manual also states that, under IEC 664, the Model 2750 is Installation Category I and must not be connected to mains.

In plain terms: the 2750 and its switching channels are for low-voltage signals on test systems and bench circuits. They are not a substitute for a meter with a mains rating. A wall outlet and a service panel are not places to connect this system. Mains and panel work is dangerous, and it belongs to a licensed electrician. The manual also warns that if a circuit can operate at 1000 V or more, no conductive part of the circuit may be exposed.

The service manual, document 2750-902-01 Rev. A, repeats the same Installation Category statement. Keep both manuals with the unit, and read the module section for each module you plan to use.

Interfaces and programming

The user’s manual has chapters on remote programming, limits and digital I/O, and the switching commands. It lists IEEE-488 connector location and the digital I/O port among its topics, and it includes sections on closing and opening switching module channels from the front panel and remotely. The datasheet describes TestPoint start-up software and driver support for LabVIEW, LabWindows/CVI, Visual Basic, and C/C++, and an optional ExceLINX datalogging package.

If your system uses a different bus or software stack, check the interface options on the manual’s specification appendix and confirm them with Tektronix for the order you plan to place.

Low-ohms and dry-circuit features

The datasheet describes a built-in 20 mV clamp for dry-circuit testing, and it says the 2750 can handle series lead resistances of up to 80% of range while still meeting specification. It also lists offset compensation and open test lead indication for production testing. These features suit low-resistance work on connectors, relays, and harnesses. They are not a substitute for a dedicated micro-ohmmeter if your measurement needs a different test current or a different setup.

Who the 2750 suits

From its documents, the 2750 is built for test racks and data acquisition systems that need many channels, a single meter, and programmable switching. Production test, research setups, and multi-point resistance checks are the kinds of work its datasheet describes. For a single meter on a bench, a handheld multimeter with a printed CAT rating suited to the circuit is the simpler choice. For a home outlet, a car battery, or a fuse check, the 2750 is not the right tool. For the meaning of the dial symbols on a handheld meter, see our guide to reading multimeter symbols, and for a related read on choosing a meter, see our true RMS multimeter guide.

How we chose

This is a model explainer, not a ranking. We read the datasheet, the user’s manual Rev. C, and the service manual Rev. A, and we wrote down only the figures and statements each document gives. We did not use distributor listings, retailer pages, or review sites.

What we could not verify

• The full numeric accuracy tables for the DMM. The datasheet we read gives headline figures, and we did not read the accuracy tables for every range.
• Whether your unit is covered by a later revision. The copies we opened are the user’s manual Rev. C (printed 11/02) and the service manual Rev. A (March 2001).
• The current price, stock, or lead times for the mainframe or its modules. These are not part of this explainer.
• The voltage and current limits of every switching module in the Keithley range. The 7700-series table is the only module table we read.

FAQ

Is the Keithley 2750 a multimeter?

Yes, with switching added. The datasheet describes a 6½-digit, 14-function DMM inside a five-slot mainframe that handles up to 200 channels of two-pole switching.

Can I connect it to mains?

No. The user’s manual states the Model 2750 is Installation Category I and must not be connected to mains. Most signals on the instrument are Installation Category I.

How many channels can it switch?

The datasheet says up to 200 differential input channels with 300 V isolation, using plug-in switching modules. The number you get depends on the modules you install.

Is it good for low-resistance measurements?

The datasheet describes low-ohms features, including a 20 mV clamp for dry-circuit testing and open test lead indication. Check the resistance ranges and test conditions in the manual for your measurement.

What is the highest voltage a module can measure?

The manual gives limits by module. For the 7700-series modules it lists 300 V maximum for measuring volts on most models and 150 V on the 7701. Read the table for the module you plan to use.

Which software does it support?

The datasheet lists TestPoint start-up software and driver support for LabVIEW, LabWindows/CVI, Visual Basic, and C/C++, plus an optional ExceLINX datalogging package.

Bottom line

The Keithley 2750 is a multimeter and switching mainframe for test racks and data acquisition systems, not a meter for mains. Before you buy, confirm the switching modules you need, check the voltage limit for each module, and read the Installation Category I statement in the user’s manual. If your work is a single bench meter or a mains check, a different instrument will suit you better.

Sources

• Keithley Instruments, Model 2750 Multimeter/Switch System datasheet (copy hosted on xdevs.com: https://xdevs.com/doc/Keithley/2750/2750_DS.pdf). Opened 2026-10-27. Third-party copy of a manufacturer document; no document number printed in the copy.
• Keithley Instruments, Model 2750 Multimeter/Switch System User’s Manual, document 2750-900-01 Rev. C (copy hosted on xdevs.com: https://xdevs.com/doc/Keithley/2750/2750_UM.pdf). Opened 2026-10-27. Third-party copy of a manufacturer document.
• Keithley Instruments, Model 2750 Service Manual, document 2750-902-01 Rev. A, March 2001 (copy hosted on xdevs.com: https://xdevs.com/doc/Keithley/2750/2750_902_01A.pdf). Opened 2026-10-27. Third-party copy of a manufacturer document.