Controlair Type Transducer
Marsh Bellofram Type Transducer
Flowserve Type Transducer
EPC Type TransducerTD7800 Electro Pneumatic Converter
The TD7800 converter is the DIN 43650 build of the T7800 family specified on the voltage input: 0-10 VDC or 1-9 VDC on a three-wire connection, 10 kilohm signal impedance, 7.2 to 30 VDC supply at less than 3 mA. It is the plug-in precision converter for a plant that signals in volts.
What This Model Is
The TD7800 Series transducers provide maximum versatility for precision applications. As a converter the instrument takes the voltage output of a controller straight into the piezoelectric primary section, with no intermediate signal conditioning, and terminates through the DIN 43650 plug used across European-built plant.
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 Converter On Our Benches
Studio and workshop photographs of the units as built, not renderings.
What You Get From This Model
Voltage in, air out, one instrument
0-10 VDC and 1-9 VDC are native inputs at 10 kilohms, so no converter stage sits in front of the transducer.
Wide supply window
7.2 to 30 VDC at less than 3 mA on the three-wire connection, which most controller supplies satisfy without modification.
Plug-in service
The DIN 43650 connector isolates the instrument electrically in one action.
Precision unchanged by the input type
0.25% full scale guaranteed accuracy, 0.1% hysteresis and repeatability, 0.02% deadband, no measurable position or supply pressure effect.
Where It Is Used
- Voltage-signalled control loops on pneumatic final elements
- Cabinet-mounted converters in DIN-wired plant
- Split range control of two functions from one voltage source
- Precision pressure regulation indoors and outdoors
- Retrofit of a voltage-output controller onto pneumatic valves
Who Orders It
- Plants with 0-10 V control signalling
- Panel builders using DIN 43650 throughout
- Integrators bridging an electronic controller to pneumatic valves
- Engineers replacing a failed voltage-input converter
What This Model Fixes
The controller outputs volts and the transducer wants milliamps
The three-wire voltage input removes the conversion stage entirely.
Loop loading is unclear
The signal impedance for the three-wire voltage input is published at 10 kilohms.
The instrument has to come out quickly
The DIN 43650 connector unplugs without touching field wiring.
Damping is wrong for the process
The damping adjustment tunes the response on the instrument.
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
- Three-wire voltage input, 7.2 to 30 VDC at less than 3 mA
- 10 kilohm signal impedance
- 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
- Verify the controller can drive 10 kilohmsThe three-wire voltage input presents 10 kilohms. Confirm the controller output stage before wiring.
- Wire three conductors, not twoA voltage input needs the third conductor. A two-wire cable pulled for a current loop will not serve.
- Pick the output range and its supply3-15 psig needs 20-120 psig supply, 3-27 psig needs 32-120 psig and 6-30 psig needs 35-120 psig.
- Reseal the connectorRefit the DIN 43650 gasket so the NEMA 4X and IP65 rating is maintained.
How It Compares With The Alternatives
The TD7800 converter and transducer share the same body and the same DIN 43650 plug; the converter is ordered on the voltage input and the transducer on the 4-20 mA two-wire current input. Against the TT7800, the difference is the termination: plug rather than terminal block.
| Model | Distinguishing specification | Best suited to |
|---|---|---|
| TD7800 Electro Pneumatic Converter | DIN 43650, voltage input | Voltage-signalled loops with plug-in service |
| TD7800 Electro Pneumatic Transducer | DIN 43650, 4-20 mA two-wire | Current loops with no local power |
| TT7800 Electro Pneumatic Converter | Terminal block, voltage input | Cabled installations landed on terminals |
Related cases
- No OEM case published for this model yet.
Related articles
Industry applications
Other Models Worth Comparing
Fairchild Type TransducerTD6000 Electro Pneumatic Transducer
T6000 series with a DIN 43650 connection, same modular mounting
View specifications →
Fairchild Type TransducerT6000 Electro Pneumatic Transducer
Modular precision transducer, six input and six output ranges, conduit termination
View specifications →
Fairchild Type TransducerT7800 Electro Pneumatic Transducer
Piezoelectric precision transducer, 0.25% full scale accuracy, NEMA 4X and IP65
View specifications →
Fairchild Type TransducerTA7800 Electro Pneumatic Transducer
Extended range T7800 with a 1/2 inch NPT conduit fitting and pigtail
View specifications →Questions About The TD7800 Electro Pneumatic Converter
What input does the TD7800 converter take
0-10 VDC or 1-9 VDC on a three-wire connection, with a 7.2 to 30 VDC supply at less than 3 mA and a 10 kilohm signal impedance. 4-20 mA DC is available on the transducer build.
What is the difference from the TD7800 transducer
The input stage. Both are DIN 43650 builds of the same T7800 instrument; the converter is specified on the voltage input.
What accuracy can I quote
0.25% of full scale guaranteed and 0.15% typical to ISA S51.1.
Is the DIN connector rated for outdoor use
The enclosure is NEMA 4X, Type 4 and IP65 rated. The connector gasket has to be intact for that rating to hold.
Can two units share one voltage source
Yes. Split range operation lets a common signal source control two or more functions.
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.