gohastings.com Hastings Entertainment Oxygen Equipment HFM-I-401 Manual De Usuario

 

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The Hastings 400 Series flow meters are designed for operation with clean dry gas and in specified 

environmental conditions (See Section 1.2). The properly installed meter measures and reports the 
mass flow as an analog signal and, depending on the configuration and set up, as a digital response. 

Other features can assist in the measurement operation and provide additional functions. The following 
sections serves as a guide for correctly interpreting the analog and digital flow output, optimizing the 

performance, and using the additional features of the instrument.      

For proper operation, the ambient and gas temperatures must be such that the flow meter 

remains between -10 and 70°C. Optimal performance is achieved when the environment and 
gas temperatures are equilibrated and stable. The 400 I series is intended for use with clean, 

non-condensing gases only. Particles, contamination, condensate, or any other liquids which 
enter the flow meter body may obstruct critical flow paths in the sensor or shunt, thus causing 

erroneous readings. 

The analog output signal is proportional to mass flow rate. Each instrument is configured to 
provide one of the available forms of analog output as described in Section 2.2. The signal read 

by an indicator (for example, a process ammeter, data acquisition system, or PLC board) can 
be mapped to the measured flow rate by applying the proper conversion equation selected 

from the table below.   
Table 3-1 The Signal → Flow mapping equations    

4 -20 mA 

Flow = FS flow * (I

out

 – 4)/ 16 

0 -20 mA 

Flow = FS flow * I

out

 / 20 

0 – 5 Vdc 

Flow = FS flow * V

out

 / 5 

0 – 10 Vdc 

Flow = FS flow * V

out

 / 10 

1 – 5 Vdc 

Flow = FS flow * (V

out

 -1)/ 4 

 
Alternatively an analog display meter can indicate the flow rate directly in the desired flow 

units by setting the offset and scaling factors properly. 
The flow meter is typically able to measure and report flow which slightly exceeds the full 
scale value. Reverse or “negative” flows are indicated (to values up to 25% of full scale) by 

meters with 4-20 mA or 1-5 volt output. However, meters with 0-5 Volt, 0-10 volt or 0-20 mA 
output are limited in their ability to indicate a negative flow with the analog signal since 

negative currents or voltages cannot be generated by the meter’s circuitry.  

Many of the Hastings 400 Series flow meter’s operating parameters such as the flow 
measurement, alarm settings, status, or gas type can be read or changed by digital 

communications. The digital communications commands and protocols for each particular 
interface (RS-232, RS-485, and Ethernet) are treated in detail in the Software Manual. 

However, the function and interpretation of flow output and auxiliary input are also briefly 
presented here.