Controlair Type Transducer
Marsh Bellofram Type Transducer
Flowserve Type Transducer
EPC Type TransducerTD7800 Electro Pneumatic Transducer
The TD7800 is the DIN 43650 build of the T7800 family, catalogued in standard and extended range. On a 4-20 mA two-wire loop it needs only 7.2 VDC at 20 mA, so it runs from the controller supply with no separate power feed, and the connector comes off with a single screw.
What This Model Is
The TD7800 Series transducers provide maximum versatility for precision applications. The D field selects the DIN 43650 connection, the standard plug-in instrument termination. On the two-wire current input the required operating voltage is 7.2 VDC at 20 mA, which keeps the loop simple: signal and power on one pair.
How It Works
The Model T7800 Series converts a DC input signal to a linear proportional pneumatic output. It includes the Primary Converting Section and the pneumatic Relay Section. The piezoelectric ceramic actuator in the Primary Converting Section functions as a flapper. The flapper and nozzle work together to control the signal pressure. That signal pressure acts on the upper control diaphragm in the Relay Section, and the lower control diaphragm senses the output pressure. In extended range units an additional relay section amplifies the output pressure.
TD7800 Electro Pneumatic Transducer On Our Benches
Studio and workshop photographs of the units as built, not renderings.
What You Get From This Model
Two wires carry signal and power
7.2 VDC at 20 mA on the two-wire current input, so no separate supply has to be run to the instrument.
Unplug to isolate
A DIN 43650 connector releases with one screw, so the instrument comes out of the loop without disturbing field terminations.
Precision held under vibration
Internal electronic feedback and the piezoelectric actuator hold output pressure regardless of vibration or position.
Standard and extended range
Both are catalogued on the DIN 43650 termination.
Where It Is Used
- Two-wire 4-20 mA loops driving pneumatic final elements
- Cabinet and panel installations wired with DIN plugs
- Precision control on vibrating structures
- Outdoor installations rated NEMA 4X and IP65
- Replacement of a DIN-connected precision transducer
Who Orders It
- Plants standardising on DIN 43650 instrument connectors
- Loops with no local power available at the valve
- Instrument engineers specifying vibration-tolerant transducers
- Maintenance teams that need fast instrument isolation
What This Model Fixes
There is no power at the valve
The two-wire current input takes 7.2 VDC at 20 mA from the loop itself.
Isolating the instrument means opening terminations
The DIN 43650 plug does it in one action.
The instrument drifts on a vibrating line
Vibration effect is less than +/-1% of span at 5-15 Hz with 0.8 inch constant displacement and at 15-500 Hz at 10 G.
The loop is close to radio equipment
RFI and EMI effect is under 0.5% of span at 30 V/m band ABC and under 0.5% at 10 V/m to 2 GHz.
Features And Specifications
Every figure below is transcribed from the datasheet EAA publishes for this series. Anything not published is not listed.
- DIN 43650 electrical connection
- Two-wire current input, 7.2 VDC at 20 mA
- Standard range and extended range builds
- Field reversible output, inversely proportional to the input signal
- RFI and EMI protection
- Internal electronic feedback with a solid state controlled piezoelectric actuator
- Damping adjustment for optimum tuning response
- Split range operation from a common signal source
- Compact size for restricted spaces
- NEMA 4X, Type 4 enclosure, IP65 rated for indoor and outdoor installation
- Canadian Registration Numbers (CRN) certification for all territories and provinces
| Set point | 3 psig [0.2 BAR] (20 kPa) | 9 psig [0.6 BAR] (60 kPa) | 15 psig [1.0 BAR] (100 kPa) | 30 psig [2.0 BAR] (200 kPa) |
|---|---|---|---|---|
| Maximum air consumption, all ranges | 3.5 SCFH (0.10 m3/HR) | 7.0 SCFH (0.20 m3/HR) | 9.5 SCFH (0.27 m3/HR) | 13.5 SCFH (0.38 m3/HR) |
| Range | Low | Middle | High |
|---|---|---|---|
| Output range | 3-15 psig [0.2-1.0 BAR] (20-100 kPa) | 3-27 psig [0.2-1.8 BAR] (20-180 kPa) | 6-30 psig [0.4-2.0 BAR] (40-200 kPa) |
| Supply pressure | 20-120 psig [1.5-8.0 BAR] (150-800 kPa) | 32-120 psig [2.2-8.0 BAR] (220-800 kPa) | 35-120 psig [2.4-8.0 BAR] (240-800 kPa) |
| Minimum span | 5 psig [0.35 BAR] (35 kPa) | 10 psig [0.7 BAR] (70 kPa) | 10 psig [0.7 BAR] (70 kPa) |
| Parameter | Value |
|---|---|
| Input range | 4-20 mA DC, 0-10 VDC, 1-9 VDC |
| Flow rate | 2.5 SCFM (4.25 m3/HR) at 25 psig [1.7 BAR] (170 kPa) supply and 9 psig [0.6 BAR] (60 kPa) output, or 9.0 SCFM (15.3 m3/HR) at 120 psig [8.0 BAR] (800 kPa) supply and 9 psig output |
| Accuracy (ISA S51.1) | 0.25% full scale guaranteed, 0.15% full scale typical |
| Hysteresis (ISA S51.1) | 0.1% full scale |
| Deadband | 0.02% full scale |
| Repeatability (ISA S51.1) | 0.1% full scale |
| Frequency response | -3 dB at 5 Hz per ISA S26.4.3.1 load configuration A |
| Operating temperature | -40 F to +160 F (-40 C to +71.2 C) |
| Storage temperature | -40 F to +180 F (-40 C to +82.2 C) |
| Required operating voltage | Two-wire current input 7.2 VDC at 20 mA (4-20 mA signal); three-wire voltage input 7.2-30 VDC, less than 3 mA |
| Signal impedance | Three-wire voltage input 10 kilohms |
| Span and zero adjustment | Screwdriver adjustments located on the front of the unit |
| Position effect | No measurable effect |
| Supply pressure effect | No measurable effect |
| Temperature effect | +0.5% +0.04% per F temperature change of span, typical |
| Vibration effect | Less than +/-1% of span at 5-15 Hz with 0.8 inch constant displacement and 15-500 Hz at 10 G |
| Reverse polarity protection | No damage from reversal of normal supply current (4-20 mA) or from misapplication of up to 60 mA |
| RFI / EMI effect | Less than 0.5% of span at 30 V/m class 3 band ABC (20-1000 MHz) per SAMA PMC 33.1 1978, and less than 0.5% of span at 10 V/m to 2 GHz per EN 61000-4-3:1998 +A1, EMC Directive 89/336/EEC, European norm EN 61326 |
| Component | Material |
|---|---|
| Body and housing | Chromate treated aluminium |
| Orifice | Nickel plated brass and sapphire |
| Trim | Stainless steel, brass and zinc plated steel |
| Elastomers | Nitrile |
| Model | Electrical connection and range |
|---|---|
| TT7800 | Terminal block. Available in standard range and extended range. |
| TA7800 | 1/2 inch NPT conduit fitting with pigtail. Available in extended range. |
| TD7800 | DIN 43650 connection. Available in standard range and extended range. |
| TR7800 | For use with the TR manifold rack kit. Same as the TT7800 except that the terminal block is located on the rear. Available in standard and extended range. |
Selecting Installing And Calibrating
- Confirm loop voltage headroomThe instrument needs 7.2 VDC at 20 mA. Check that the controller supply covers that plus the rest of the loop burden.
- Match the supply to the output range20-120 psig for 3-15 psig output, 32-120 psig for 3-27 psig, 35-120 psig for 6-30 psig.
- Refit the connector gasketThe DIN 43650 plug seals on a gasket. Replace it whenever the plug is refitted.
- Check the frequency response against the loop-3 dB at 5 Hz per ISA S26.4.3.1 load configuration A, which is the figure to compare against the process time constant.
How It Compares With The Alternatives
The TD7800 transducer and the TD7800 converter share the DIN 43650 termination and the T7800 core; the transducer is specified on the 4-20 mA two-wire current input and the converter on the voltage input. Against the TD6000, the TD7800 gives published ISA accuracy where the TD6000 gives modular mounting.
| Model | Distinguishing specification | Best suited to |
|---|---|---|
| TD7800 Electro Pneumatic Transducer | DIN 43650, 4-20 mA two-wire | Current loops with no local power |
| TD7800 Electro Pneumatic Converter | DIN 43650, voltage input | Voltage-signalled loops |
| TD6000 Electro Pneumatic Transducer | DIN 43650, modular mounting | Racks, panels and manifolds |
Related cases
- No OEM case published for this model yet.
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View specifications →Questions About The TD7800 Electro Pneumatic Transducer
What voltage does the two-wire input need
7.2 VDC at 20 mA for a 4-20 mA signal. Signal and power share the one pair.
What does the D stand for
The DIN 43650 electrical connection.
Is the TD7800 available in extended range
Yes. Both standard range and extended range are catalogued.
How does it behave under vibration
Less than +/-1% of span at 5-15 Hz with 0.8 inch constant displacement and at 15-500 Hz at 10 G, and position effect is stated as no measurable effect.
What is the frequency response
-3 dB at 5 Hz per ISA S26.4.3.1 load configuration A.
Request A Price For The TD7800
Tell us the input signal, the output range and the electrical termination, and the quotation comes back against the published part number.