The Nitra NCP1 Series Electropneumatic Transducer (I/P) is a device designed to convert a current input signal into a linearly proportional pneumatic output pressure. This versatile instrument is suitable for control applications that require a high degree of reliability and repeatability at an economical cost.
Function Description
The NCP1 Series transducer operates on a force balance principle. A coil suspended in the field of a magnet is the core component. Current flowing through this coil generates an axial movement of the coil and flexure. The flexure movement then directs flow through a nozzle and creates back pressure, which acts as a pilot pressure to an integral booster relay. This input signal increase causes a proportional output pressure increase. The zero and span adjustments are made by turning adjustment screws on the front face of the unit. The zero screw repositions the nozzle relative to the flexure, while the span adjustment is a potentiometer that controls the amount of current through the coil.
Important Technical Specifications
The NCP1 Series offers various models with different input and output ranges:
- NCP1-20-315N: Input 4-20 mA, Output 3-15 psig (0.2-1.0 bar)
- NCP1-20-327N: Input 4-20 mA, Output 3-27 psig (0.2-1.8 bar)
- NCP1-20-630N: Input 4-20 mA, Output 6-30 psig (0.4-2.0 bar)
- NCP1-20-260N: Input 4-20 mA, Output 2-60 psig (0.4-4.0 bar)
- NCP1-20-2120N: Input 4-20 mA, Output 3-120 psig (0.2-8.0 bar)
Functional Specifications:
- Air Consumption: 0.05 scfm (1.4 Nl/min) midrange typical
- Flow Capacity: 4 scfm (127 Nl/min) at 25 psig (1.7 bar) supply; 2.0 scfm (56.6 Nl/min) at 20 psig (1.3 bar) supply
- Exhaust Capacity: 2 scfm (56.6 Nl/min) at 5 psig (2.4 bar) above 20 psig (1.3 bar) setpoint
- Temperature Limits: -20°F to +140°F (-30°C to +60°C)
- Impedance: Varies by model (180 Ohms for -315N, 220 Ohms for -327N, 240 Ohms for -630N, 225 Ohms for -260N, 260 Ohms for -2120N)
- Linearity: <± 0.75% of span
- Hysteresis and Repeatability: <± 1.0% of span; <± 0.5% of span
- Supply Pressure Sensitivity: <± 0.1% of span per psig (<± 0.15% of span per 0.1 bar)
- Media: Oil free, clean dry air filtered to 40 micron
- Electrical Connections: Conduit 1/2" NPT female with 12" wire leads
- Mounting: Direct or bracket (bracket included)
- Housing: Chromate-treated aluminum with epoxy paint. NEMA 4X (IP65)
- Elastomers: Buna-N
- Trim: Stainless steel, brass, zinc-plated steel
- Weight: 2.1 lbs. (0.94 kg)
- Approvals: FM (Haz-Loc)*
*Output shown is an calibrated at the factory. Large span adjustment capability allows for calibration to achieve output ranges from 3-15 psig (0.2-1.0 bar) with 2-60 psig unit to 3-145 psig (0.2-10 bar) with 3-120 psig unit.
Usage Features
- Mounting: The unit can be pipe, panel, or bracket mounted. Mounting may be at any angle, though mounting may require field adjustment. High external vibration may cause output fluctuations. Mounting in a vibration-free area is recommended.
- Pneumatic Connections: The 1/4" NPT supply and output ports are marked "IN" and "OUT" respectively on the base of the unit. Clean all pipe lines to remove contamination before installation. If thread sealer is required, use a tape type that is compatible with the media. Liquid or paste type thread sealer is not recommended.
- Air Supply: Clean dry instrument quality air must be used. To insure optimum performance supply pressure should be regulated. To provide stable inlet pressure and prevent contamination of the internal section of the transducer the use of an Instrument Air Filter Regulator is recommended.
- Alternative Output Ports: The two unmarked ports on the base of the unit are gauge ports but may be used as alternative output ports. Any unused ports must be plugged.
- Electrical Connections: Electrical connections are made to the black and white leads extending out from the 1/2" NPT conduit fitting. Black is positive, white is negative.
- Calibration: Zero and Span should always be checked after mounting. If unit is calibrated in a vertical position and then mounted at an angle, readjustment of the zero is necessary.
- Open protective covers to expose zero and span adjustment screws.
- Connect the recommended air supply to the inlet of the transducer and an accurate pressure gauge to the outlet.
- Connect the electrical input and set the input signal to 4mA.
- Observe the output pressure. If necessary, adjust the zero screw until reaching minimum output pressure setting. Turn zero screw counter-clockwise to increase pressure, clockwise to decrease pressure.
- Increase electrical input signal to 20mA.
- Observe the output pressure. If necessary adjust the span screw until reaching maximum output pressure setting. For I/P (current) input models turn span screw counter clockwise to increase pressure, clockwise to decrease pressure.
- The Zero and Span adjustments are interactive. After adjusting the span it will be necessary to recheck the zero. Repeat steps 3-6 until both end points are at the required values.
- If unable to achieve output during calibration process, follow the steps outlined in 4.1.4 to clean the orifice. Then turn zero adjustment screw counter clockwise for up to 30 revolutions, until output pressure rises.
Maintenance Features
Under normal circumstances, no maintenance should be required. However, if problems arise, troubleshooting steps are provided:
- Air Filtration: Failures due to instrument supply air contamination are not covered by warranty. Use of oil and/or water saturated instrument air can cause erratic operation. Poor quality instrument air can result in unit failure. It is recommended that a filter regulator be placed upstream of each unit where oil and or water laded instrument air is suspected.
- Cleaning the Orifice: If clean, dry air is not used the orifice can become blocked. To clean, first turn off supply air, unscrew and remove orifice assembly (large silver screw head located above the out port). Then, unplug orifice by using a wire that has a smaller diameter than 0.015 in. (0.38 mm). Use compressed air to blow out any loose particles inside the orifice assembly. Screw orifice assembly back into unit.
Troubleshooting Guide:
| Problem | Look For | Solution Function Description
The Nitra NCP1 Series Electropneumatic Transducer (I/P) is a device designed to convert a current input signal into a linearly proportional pneumatic output pressure. This versatile instrument is suitable for control applications that require a high degree of reliability and repeatability at an economical cost.
Important Technical Specifications
The NCP1 Series offers various models with different input and output ranges:
- NCP1-20-315N: Input 4-20 mA, Output 3-15 psig (0.2-1.0 bar)
- NCP1-20-327N: Input 4-20 mA, Output 3-27 psig (0.2-1.8 bar)
- NCP1-20-630N: Input 4-20 mA, Output 6-30 psig (0.4-2.0 bar)
- NCP1-20-260N: Input 4-20 mA, Output 2-60 psig (0.4-4.0 bar)
- NCP1-20-2120N: Input 4-20 mA, Output 3-120 psig (0.2-8.0 bar)
Functional Specifications:
- Air Consumption: 0.05 scfm (1.4 Nl/min) midrange typical
- Flow Capacity: 4 scfm (127 Nl/min) at 25 psig (1.7 bar) supply; 2.0 scfm (56.6 Nl/min) at 20 psig (1.3 bar) supply
- Exhaust Capacity: 2 scfm (56.6 Nl/min) at 5 psig (2.4 bar) above 20 psig (1.3 bar) setpoint
- Temperature Limits: -20°F to +140°F (-30°C to +60°C)
- Impedance: Varies by model (180 Ohms for -315N, 220 Ohms for -327N, 240 Ohms for -630N, 225 Ohms for -260N, 260 Ohms for -2120N)
- Linearity: <± 0.75% of span
- Hysteresis and Repeatability: <± 1.0% of span; <± 0.5% of span
- Supply Pressure Sensitivity: <± 0.1% of span per psig (<± 0.15% of span per 0.1 bar)
- Media: Oil free, clean dry air filtered to 40 micron
- Electrical Connections: Conduit 1/2" NPT female with 12" wire leads
- Mounting: Direct or bracket (bracket included)
- Housing: Chromate-treated aluminum with epoxy paint. NEMA 4X (IP65)
- Elastomers: Buna-N
- Trim: Stainless steel, brass, zinc-plated steel
- Weight: 2.1 lbs. (0.94 kg)
- Approvals: FM (Haz-Loc)*
*Output shown is an calibrated at the factory. Large span adjustment capability allows for calibration to achieve output ranges from 3-15 psig (0.2-1.0 bar) with 2-60 psig unit to 3-145 psig (0.2-10 bar) with 3-120 psig unit.
Usage Features
- Mounting: The unit can be pipe, panel, or bracket mounted. Mounting may be at any angle, though mounting may require field adjustment. High external vibration may cause output fluctuations. Mounting in a vibration-free area is recommended.
- Pneumatic Connections: The 1/4" NPT supply and output ports are marked "IN" and "OUT" respectively on the base of the unit. Clean all pipe lines to remove contamination before installation. If thread sealer is required, use a tape type that is compatible with the media. Liquid or paste type thread sealer is not recommended.
- Air Supply: Clean dry instrument quality air must be used. To insure optimum performance supply pressure should be regulated. To provide stable inlet pressure and prevent contamination of the internal section of the transducer the use of an Instrument Air Filter Regulator is recommended.
- Alternative Output Ports: The two unmarked ports on the base of the unit are gauge ports but may be used as alternative output ports. Any unused ports must be plugged.
- Electrical Connections: Electrical connections are made to the black and white leads extending out from the 1/2" NPT conduit fitting. Black is positive, white is negative.
- Calibration: Zero and Span should always be checked after mounting. If unit is calibrated in a vertical position and then mounted at an angle, readjustment of the zero is necessary.
- Open protective covers to expose zero and span adjustment screws.
- Connect the recommended air supply to the inlet of the transducer and an accurate pressure gauge to the outlet.
- Connect the electrical input and set the input signal to 4mA.
- Observe the output pressure. If necessary, adjust the zero screw until reaching minimum output pressure setting. Turn zero screw counter-clockwise to increase pressure, clockwise to decrease pressure.
- Increase electrical input signal to 20mA.
- Observe the output pressure. If necessary adjust the span screw until reaching maximum output pressure setting. For I/P (current) input models turn span screw counter clockwise to increase pressure, clockwise to decrease pressure.
- The Zero and Span adjustments are interactive. After adjusting the span it will be necessary to recheck the zero. Repeat steps 3-6 until both end points are at the required values.
- If unable to achieve output during calibration process, follow the steps outlined in 4.1.4 to clean the orifice. Then turn zero adjustment screw counter clockwise for up to 30 revolutions, until output pressure rises.
Maintenance Features
Under normal circumstances, no maintenance should be required. However, if problems arise, troubleshooting steps are provided:
- Air Filtration: Failures due to instrument supply air contamination are not covered by warranty. Use of oil and/or water saturated instrument air can cause erratic operation. Poor quality instrument air can result in unit failure. It is recommended that a filter regulator be placed upstream of each unit where oil and or water laded instrument air is suspected.
- Cleaning the Orifice: If clean, dry air is not used the orifice can become blocked. To clean, first turn off supply air, unscrew and remove orifice assembly (large silver screw head located above the out port). Then, unplug orifice by using a wire that has a smaller diameter than 0.015 in. (0.38 mm). Use compressed air to blow out any loose particles inside the orifice assembly. Screw orifice assembly back into unit.
Troubleshooting Guide:
| Problem | Look For | Solution
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