MKS 220DD-00100A2B 100 Torr Differential Manometer

Description

Product Introduction & Engineering Value

The 220DD-00100A2B is intended for applications where low differential pressure must be converted into a stable electrical signal for process instrumentation, vacuum equipment, or control hardware. Its all-metal sensing structure uses diaphragm deflection to produce a capacitance change that is amplified, demodulated, and converted into a pressure-proportional DC output.

The heated 45°C sensor construction is significant. Temperature control helps reduce zero and span drift caused by changes in the surrounding environment. The unit provides both 0–10 VDC and 4–20 mA interfaces, making it practical for integration with conventional process controllers and instrumentation systems.

Technical Specifications

MKS specifies Inconel construction on the Px side, while the reference side incorporates Inconel, ceramic, palladium, stainless steel, and glass materials. The published specification also gives a 7.0 cc Px-side volume and 19.0 cc reference-side volume.

A specification discrepancy worth flagging

Some third-party listings describe this exact model with conflicting pressure ranges, output configurations, or connection details. MKS’s own product page identifies 220DD-00100A2B as a 100 Torr, 0.5-inch OD tube, 45°C configuration and should take precedence when preparing a purchase specification.

220DD-00100A2B

220DD-00100A2B

Field Application & the “Trench” Experience

A common replacement scenario occurs on a vacuum process skid where the original differential-pressure transducer has developed an unstable zero. The PLC still receives a signal, but the baseline slowly shifts as the equipment temperature changes. Operators compensate manually, which creates another problem: the pressure reading no longer agrees with the calibrated reference instrument.

Replacing the transducer with the correct 220DD configuration is only the first step. The maintenance team must verify the process tubing, Px/Pr port arrangement, electrical supply, analog-output scaling, grounding, and zero condition before returning the measurement loop to service.

The 220DD’s heated sensing element is particularly useful in applications where ambient temperature changes would otherwise influence low-pressure measurements. MKS specifically designed the sensor around a controlled 45°C operating point to improve zero and span stability.

Niche application scenarios

Vacuum deposition chamber pressure monitoring
Monitor differential pressure associated with chamber or process-gas conditions where stable low-pressure measurement is required.

Semiconductor process equipment
Use the manometer as an analog pressure-feedback element in vacuum and process-control equipment.

Gas-flow differential measurement
Measure relatively small pressure differences across process components where a conventional high-range pressure transmitter would sacrifice useful resolution.

Laboratory vacuum instrumentation
The device can serve as a low-pressure measurement element in specialized research and analytical equipment. The model has also been used in experimental pressure-measurement applications outside conventional industrial process equipment.

Transparency SOP: QA & Testing

For New Surplus or Refurbished inventory, the correct approach is to test the instrument as a pressure-measurement device rather than simply applying power and checking whether an indicator responds.

1. Part-number verification
   Confirm the complete marking 220DD-00100A2B, including all suffix characters.
2. Mechanical inspection
   Inspect the process tube connection, housing, electrical connector, mounting hardware, and visible surfaces for impact or corrosion damage.
3. Electrical power test
   Verify operation using the specified 115/230 VAC supply configuration.
4. Output verification
   Check the 0–10 VDC and 4–20 mA outputs for sensible response and electrical stability.
5. Pressure-response test
   Apply controlled differential pressure across the measurement ports and compare the output against a calibrated reference.
6. Zero verification
   Confirm the zero point after the instrument reaches its intended thermal condition.
7. Final documentation
   Record model number, serial number where available, physical condition, test conditions, and measured output before shipment.

For critical vacuum equipment, a simple power-on test is not sufficient evidence of measurement accuracy.

The Veteran’s Tech Trap Guide

⚠️ Trap #1 — Confusing differential and absolute-pressure models

The 220DD is a differential capacitance manometer. Do not substitute an absolute-pressure Baratron simply because its pressure range looks similar. The Px and reference sides are part of the measurement architecture. MKS explicitly identifies this model as differential.

⚠️ Trap #2 — Ignoring the suffix

The complete designation is 220DD-00100A2B. The suffix is not cosmetic. Process connection, electrical interface, pressure range, and configuration details can vary across pressure-transducer variants. Verify the complete ordering number against the installed instrument and engineering documentation.

⚠️ Trap #3 — Treating the output as a generic 4–20 mA transmitter

The MKS specification identifies both 0–10 VDC and 4–20 mA outputs. Confirm the receiving instrument’s scaling and wiring before commissioning. A correct pressure sensor with incorrect PLC/DCS scaling can still produce an incorrect process value.

PRO TIP: When replacing an installed unit, photograph the existing wiring and record the PLC/DCS engineering-unit scaling before disconnecting the old transducer. For low-pressure measurement, a wiring mistake or incorrect zero can be much harder to diagnose than a completely dead instrument.

Dynamic FAQ

What is the MKS 220DD-00100A2B?

It is an MKS 220DD Baratron heated differential capacitance manometer used for low differential-pressure measurement. The specified configuration has a 100 Torr full-scale range and 45°C sensor temperature.

What is the pressure range?

MKS lists the 220DD-00100A2B with a 100 Torr full-scale differential-pressure range.

What outputs does it provide?

The MKS specification identifies 0–10 VDC and 4–20 mA analog outputs. The electrical interface uses a 6-pin circular connector.

What process connection does this model use?

The specified 220DD-00100A2B configuration uses a 0.5-inch OD tube fitting. This should be verified against the physical unit before installation, particularly when replacing an older instrument.

Is 220DD-00100A2B a PLC module?

No. It is a pressure measurement instrument, specifically a Baratron differential capacitance manometer. Some industrial automation inventory websites categorize it alongside control modules, but that does not change its actual function. MKS identifies it as a vacuum pressure transducer/manometer.

What does “New Surplus” mean for this MKS instrument?

New Surplus normally means unused inventory that was obtained outside the manufacturer’s current direct-sales channel. It should not automatically be described as current-production factory stock. For procurement, request the actual unit’s photographs, complete model number, serial information where available, condition statement, and test documentation.

What warranty should apply?

Warranty depends on the seller and the stock condition. For industrial vacuum instrumentation, obtain the warranty period and return terms in writing before purchase. A seller warranty should also be distinguished from an MKS factory warranty.