Marsh Bellofram Type Transducer
Fairchild Type Transducer
EPC Type TransducerPT700 Electro Pneumatic Transducer
The PT 700 series provides proportional conversion from a 4-20 mA input signal to a 0-100% supply pressure output. It is the first of these transducers to use piezoelectric microvalves with low power consumption, which is what allows connection to standard two-wire circuits with no extra power supply.
What This Model Is
The PT 700 series provides the interface between an electro-pneumatic positioner and a pneumatic actuator in process industrial applications: chemical, petrochemical and refinery duty. The units are easy to adapt and improve the performance of the control loop with optimised dynamic behaviour. Because no extra power supply is needed, the device stays compact and robust.
How It Works
Conversion of the electrical input signal is made accurate by a silicon pressure sensor providing feedback, and an internal pressure regulator eliminates variations in supply air pressure. The internal control loop runs PI control characteristics, which is what gives the precise control performance and high dynamic behaviour the series is specified on.
PT700 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, no separate supply
Piezoelectric microvalves with low power consumption allow connection to standard two-wire circuits. Current supply runs from 3.6 mA minimum, and the load is 300 ohm at 20 mA.
Intrinsically safe to ATEX
ATEX II 1 G EEx ia IIC T4 on the PT715 build, with IP66 and NEMA 4X ingress protection on a die cast aluminium housing.
Supply variation removed at the instrument
The internal pressure regulator eliminates variations in supply air pressure, so a moving header does not move the output.
NAMUR mounting in stainless steel
A universal mounting kit to NAMUR specifications in stainless steel, plus direct mounting options to Flowact and VDI/VDE 3847 and a wall or 2 inch pipe bracket.
Where It Is Used
- Chemical process plant
- Petrochemical plant and refineries
- Interfacing an electro-pneumatic positioner to a pneumatic actuator
- Intrinsically safe loops in classified areas
- Installations with high shock and vibration
Who Orders It
- Refinery and petrochemical instrument engineers
- Plants working to NAMUR and VDI/VDE mounting standards
- Loops that must be intrinsically safe on two wires
- Maintenance teams replacing a PT 700 pattern unit
What This Model Fixes
A hazardous area loop cannot carry a separate supply
The two-wire system carries signal and power on one pair, and the PT715 build is intrinsically safe to ATEX II 1 G EEx ia IIC T4.
Supply air pressure wanders
The built-in pressure regulator eliminates supply variation at the instrument itself.
Shock and vibration upset the output
Vibration sensitivity is below 1% at 1 and 2 g over 3-300 Hz according to IEC 61514, and mounting position effect is below 0.25%.
Maintenance means replacing the whole unit
The robust modular design makes maintenance straightforward rather than a swap-out.
Features And Specifications
Every figure below is transcribed from the datasheet EAA publishes for this series. Anything not published is not listed.
- Accurate conversion using a silicon pressure sensor for feedback
- Robust modular design
- Pressure regulator eliminates variations in supply air pressure
- Piezoelectric microvalve transducer technology
- Input signal 4-20 mA with split range start at 4 mA or 12 mA
- High resistance against shock and vibration
- Two wire system for signal and power supply line
- Universal mounting kit according to NAMUR specifications in stainless steel
- PI control characteristics in the internal control loop
| Parameter | Value |
|---|---|
| Input signal | 4-20 mA |
| Split range | 4-12 mA, 12-20 mA |
| Current supply min | 3.6 mA |
| Current supply max | 100 mA |
| Load | 300 ohm at 20 mA |
| Voltage min | 6 VDC |
| Voltage max | 9.5 VDC |
| Air supply | 1.5-6 bar |
| Output | 0-4 bar |
| Air supply quality | Free from oil, dust and moisture, ISO 8573-1 Class 1,2 |
| Ingress protection | IP66 / NEMA 4X |
| Operating humidity | 0-95% rh |
| Air connections | 1/4 inch NPT |
| Cable entry | 2 x 1/2 inch or M20 x 1.5 |
| Terminals | Screw terminals 2.5 mm2 (AWG 14) |
| Operating temperature | -20 to +85 C; -40 to +85 C optional |
| Storing temperature | -40 to +85 C |
| Air delivery capacity | 7 Nm3/h at 6 bar |
| Air consumption | 0.12 Nm3/h at 6 bar |
| Linearity | <1% |
| Sensitivity | <0.1% |
| Repeatability | <0.2% |
| Dead band | <0.1% |
| Hysteresis | <0.5% |
| Temperature effect | <0.5% per 10 K |
| Mounting position | <0.25% |
| Vibration sensitivity | <1% at 1 and 2 g, 3-300 Hz according to IEC 61514 |
| CE | 84/336 EEC |
| Approvals | ATEX II 1 G EEx ia IIC T4 |
| Housing material | Die cast aluminium |
| Surface treatment | Powder paint |
| Soft goods | Nitrile |
| Weight | 1.5 kg |
| Base model | Meaning |
|---|---|
| PT700 | Standard, no approval |
| PT715 | Intrinsically safe, ATEX II 1 G EEx ia IIC T4 |
| A - Housing | Meaning |
|---|---|
| W | Aluminium, black with white cover, no window |
| Y | Aluminium, black with yellow cover, no window |
| B | Aluminium, black with black cover, no window |
| B - Threaded connections | Meaning |
|---|---|
| 1 | 1/2 NPT conduit, 1/4 NPT pneumatic |
| 2 | M20 x 1.5 conduit, 1/4 NPT pneumatic |
| C - Operating temperature | Meaning |
|---|---|
| S | Standard -20 C to 80 C (-4 F to 176 F) |
| E | Extended -40 C to 80 C (-40 F to 176 F) |
| D - Gauge options | Meaning |
|---|---|
| 0 | No gauges |
| 1 | Output, PSI/BAR/KPA stainless with brass internals |
| 2 | Output and supply, PSI/BAR/KPA stainless with brass internals |
| 3 | Output, PSI/BAR/KPA stainless with stainless internals |
| 4 | Output and supply, PSI/BAR/KPA stainless with stainless internals |
| Mounting options | Meaning |
|---|---|
| A | Flowact direct mounting, part 30144 |
| B | VDI/VDE 3847 direct mounting, part 30145 |
| C | IEC 534-6 NAMUR linear mounting, part 30168S |
| D | Wall or 2 inch pipe mounting bracket, part D3R-AS6 |
Selecting Installing And Calibrating
- Check the loop can supply the load300 ohm at 20 mA, 6 VDC minimum and 9.5 VDC maximum at the terminals, with a minimum current supply of 3.6 mA.
- Treat the air to ISO 8573-1 Class 1,2Air supply has to be free from oil, dust and moisture. Supply pressure is 1.5-6 bar and output is 0-4 bar.
- Choose the mounting kitFlowact direct mounting part 30144, VDI/VDE 3847 direct mounting part 30145, IEC 534-6 NAMUR linear mounting part 30168S, or the wall and 2 inch pipe bracket D3R-AS6.
- Set split range if two devices share the signalThe split range start is selectable at 4 mA or 12 mA, giving 4-12 mA and 12-20 mA halves.
How It Compares With The Alternatives
The PT700 is the two-wire intrinsically safe instrument in the range. Against the T7800 it gives ATEX EEx ia and IP66 with a NAMUR mounting kit, where the T7800 gives tighter published ISA accuracy figures and a wider set of electrical terminations. Against the 500X and T1000 patterns it is the modern piezoelectric design rather than a force balance one.
| Model | Distinguishing specification | Best suited to |
|---|---|---|
| PT700 Electro Pneumatic Transducer | Two-wire, ATEX EEx ia IIC T4, IP66 | Intrinsically safe loops in hazardous areas |
| T7800 Electro Pneumatic Transducer | 0.25% FS accuracy, NEMA 4X and IP65 | Precision loops in general purpose areas |
| T1000 Electro Pneumatic Transducer | Force balance, 12-24 SCFM | High flow duty |
Related cases
- No OEM case published for this model yet.
Related articles
Industry applications
Other Models Worth Comparing
Controlair Type Transducer500X Electro Pneumatic Transducer
Controlair pattern I/P transducer, 4-20 mA in, 3-15 to 3-120 psi out
View specifications →
Controlair Type Transducer500X Electro Pneumatic Converter
Controlair pattern E/P converter, 0-5 V, 1-9 V and 0-10 V inputs
View specifications →
Controlair Type Transducer500AC Electro Pneumatic Transducer
500-AC configuration, 4-20 mA in, 3-15 psi out, 180 ohms
View specifications →
Controlair Type Transducer500ACD Electro Pneumatic Transducer
500-AC range with a plug-in electrical termination
View specifications →Questions About The PT700 Electro Pneumatic Transducer
Does the PT700 need a separate power supply
No. The piezoelectric microvalves consume little enough power for the device to run on a standard two-wire circuit carrying both signal and supply.
What hazardous area approval does it carry
ATEX II 1 G EEx ia IIC T4 on the intrinsically safe build, which is ordered as the PT715. The standard build, PT700, is supplied without approval.
What air supply does it take
1.5-6 bar, free from oil, dust and moisture to ISO 8573-1 Class 1,2. Output is 0-4 bar, air delivery capacity is 7 Nm3/h at 6 bar and consumption is 0.12 Nm3/h at 6 bar.
What are the accuracy figures
Linearity below 1%, sensitivity below 0.1%, repeatability below 0.2%, dead band below 0.1%, hysteresis below 0.5% and temperature effect below 0.5% per 10 K.
What temperature range is available
Standard operating temperature is -20 to +85 C, with -40 to +85 C available as an option. Storage is -40 to +85 C.
Request A Price For The PT700
Tell us the input signal, the output range and the electrical termination, and the quotation comes back against the published part number.