Contrec's 415 Steam and Gas Flow Computer incorporates the following compensation equations for gas and vapours:
Ideal Gas Law using temperature and pressure correction, but where compressibility correction is not required.
General Gases where compressibility is calculated using the RedlichKwong¹ state equation. This equation is suitable for gases which have known properties, and information on common industrial gases is provided in the operating manual.
Natural Gas using the NX19² equation to calculate super compressibility.
Steam Equations for both saturated and superheated steam. Mass and energy flow rates are calculated using standard equations to determine the specific weight and enthalpy of steam.
Programming is simplified with the 415's backlit alphanumeric display providing a clear indication of all parameters, as well as engineering units. The 415 is fully programmable and all operating parameters are entered via the front panel keypad. This instrument is available with direct RTD input (415R) or with 420mA temperature input (415A). Both accept a 420mA pressure input. Inputs from a wide range of flowmeters are accepted, including vortex, turbine, orifice plate, averaging pitot tubes, wedges and target flowmeters. Where two differential pressure transmitters are used across an orifice or similar device, to increase the measured flow range, both DP transmitter inputs are accepted and scaled separately with automatic crossover.
 Displays mass flow, corrected volume and energy flow
 Accepts 420mA and frequency flow inputs
 Temperature and pressure compensation
 Dual ranged DP transmitter inputs
 Operates from 1428V dc or ac mains
 Simplified programming
 Data logging output
GENERAL SPECIFICATIONS  Display  2 line x 20 character (5.5mm high) alphanumeric backlit LCD. 
Keypad  Sealed membrane keypad with four keys.  
Power 


Temperature 
0 to 55°C 

Sealing  IP65 (Nema 4X) watertight  
APPROVALS  Electrical  ETL (US) approved to UL508 and CSA 
Interface  CE Compliance  
Enclosure  CENELEC, FM, CSA and SAA approved enclosures available for hazardous areas  
Frequency Input  Range 

Input Circuits  Accepts most sine, logic and proximity switch inputs  
Kfactor Range  0.1000 to 999,999  
NonLinear Correction  Up to 10 correction points  
420mA Inputs  Input Types  Flow (2 ranges), pressure and temperature 
Input Impedance  250 ohms  
Measurement Range 


Span (flow)  999,999  
Accuracy  0.05%  
Circuit  250 ohm resistors connected to a common signal ground (current sinking)  
NonLinear Correction  A 20 point curve can be applied to the flow input  
RTD Input (Model 415R)  Type  Platinum PT100 
Range  100°C (l48°F) to 200°C (392°F). (Note a wider temperature range can be handled via a 420mA input.)  
Accuracy  0.1°C  
Linearity  The nonlinearity of the RTD is internally compensated for  
Pressure Input  Type  Absolute or gauge 
Span  Absolute or gauge pressure is programmable at 4mA and 20mA  
Atmospheric  If a gauge pressure sensor is used, the atmospheric pressure is programmable  
Pulse Output  Pulse Width  l0ms (negative going pulse). 
Duty Cycle  49 pulses/sec max  
Output  Open collector transistor will sink l00mA max. (Note: Suitable for driving remote counters or PLC's.)  
RS232/422 Option  Type  Both RS232 and RS422 are provided. (Note: When using the RS422, multipoint communication (RS485) can be implemented with up to 32 instruments connected to a common bus.) 
Function  Printer and computer protocols are fully programmable.  
Printer  A print is initiated on each reset or at a programmable time interval. (Note: Protocols are provided for roll & column printers.)  
Computer  An ASCII based protocol enables all displayed parameters to be read and the totals to be reset  
Baud rate  300 to 9600  
Data Bits  7 or 8  
Parity  None, Odd or Even  
Data Logging  Output generated at intervals of once a minute to once every 24 hours. The totals can be programmed to reset on each print or at 24:00 hours.  
Time  A real time clock is provided to give time and date on each output  
420mA Output Option  Function  Outputs flow rate in mass, corrected volume or energy. The 4 and 20mA points can be programmed to provide a fully scaled output. 
Resolution  10 bits  
Accuracy  Better than 0.1%  
Maximum Load  500 ohms internally powered. 950 ohms from external 24V dc  
Isolation  Output is isolated  
Relay Output Option  Function  High and low flow rate alarms based on the flow rate in mass, corrected volume or energy. 
Maximum Ratings 
Power: 250VA.
Voltage: 250V ac, 30V dc.
Current: 5 Amps.


Ideal Gas 
Display 

Temp Range  273°C to 800°C  
Pressure Range  0 kPa abs (0 psia) to 100,000 kPa abs (10,000 psia)  
General Gas  Gases  Handles most gases for which the critical temperature, pressure and specific gravity are known 
Compressibility  Calculated using the RedlichKwong equation  
Temp Range  273°C to 800°C (RTD has a more limited range)  
Pressure Range  0 kPa abs (0 psia) to 100,000 kPa abs (10,000 psia)  
Natural Gas  Calculations  Uses NX19 equation to calculate super compressibility F_{PV} 
Temp Range  40°C (40°F) to 115°C (240°F)  
Pressure Range  101.325 kPa abs (14.69 psia) to 34,380 kPa abs (4985 psia).  
Specific Gravity Range  0.554 to 1.000  
Carbon Dioxide  0 to 15% mole  
Nitrogen  0 to 15% mole  
Steam  Calculations  Uses 1967 IFC Formulation (ASME) equations to calculate specific weight and enthalpy of steam. 
Types  Saturated and Superheated.  
Temp Range  20°C to 800°C (RTD has a more limited range.)  
Pressure Range  1 kPa abs (1 psia) to 100,000 kPa abs (10,000 psia).  
Saturated Steam  When measuring saturated steam, it is possible to omit either the pressure or temperature sensor since, on the saturated line, there is a corresponding pressure for all temperatures. 
Important: Specifications are subject to change without notice.
The 415 accepts most flowmeter inputs including:
 Frequency producing flowmeters such as vortex, turbine or positive displacement.
 Volumetric flowmeters with 420mA outputs such as vortex or turbines with a frequency to current converter on the output.
 Differential Pressure devices such as orifice plates, averaging pitot tubes, wedges, cones, elbows or target flowmeters, where a square law relationship applies.
 Linear Differential Pressure devices where the 420mA output is directly proportional to the flow rate.
 Dual Range (Stacked) Differential Pressure Transmitters where two separately spanned transmitters are used across a common flow device such as an orifice (both square and linear inputs).
 NonLinear Differential Pressure devices such as laminar flow tubes or VA meters. A 20 point correction curve can be programmed to compensate for any nonlinearities in the flowmeter.
Information is displayed in a number of windows which can be selected using the DISPLAY key.
General
Gas Flow
Steam Flow