9 Aug 10 18:54
bear with me as i'm a gearhead . . .
there is a fuel meter that measures gas flow (acf-actual cubic feet) and with an internal p & T sensor, which converts acf to scf (standard cubic feet). the meter output signal has 3 FULLY PROGRAMMABLE PULSE OUTPUTS
Corrected, Uncorrected, and Alarm/Fault:
Loop Voltage: 5-15 Vdc
Loop Current: 10 mA maximum
Pulse Width: 62.5, 125, 187, or 312 ms
On/Off Resistance: <10_/> 10MΩ
Isolation: 2,500 Vdc
for a user configurable setting of 1-pulse output signal per 10 scf (1, 10, 100, & 1,000-scf are the choices) gas flow, pulse width of 125-ms, and max gas flow of 500-scfm, this output signal needs to be converted to a 4-20mA signal - input signal to AB Control Logix PLC.
an API 4380 (http://www.api-usa.com/pdf/api/apd4380.pdf
) is being considered to convert the signal. the concern is with the pulse output signal, it will result in a fluctuating or pulsating 4-20mA signal which MAY result in an erratic display.
an option being considered is an input card for the PLC, but this MAY be a little more expensive.
please advise on other options to consider or how best to convert the pulse output signal to a steady 4-20mA input signal to PLC. the meter OEM does not provide such a device.