Foxboro E69F Converter

Foxboro E69F Converter

Foxboro E69F on-site installed current pneumatic signal converter is used to convert standard DC input signals into proportional pneumatic outputs for driving other pneumatic instruments or control valves. It has a small size and flexible installation, and can be fixed on surfaces, valve yokes, or DN50/2-inch vertical pipes. When replacing or troubleshooting on site, one should not only focus on the "4-20mA input, 3-15psi output" line, but also check the housing type, input range, output range, positive and negative effects, split range settings, electrical safety classification, and optional components together. Otherwise, it is easy to encounter problems such as "new parts installed but not functioning, output reverse, and not suitable for explosion-proof areas".

Confirm the model and function first, then discuss replacement

The E69F model number consists of a housing, input, output, and optional components. The shell "- B" is a bolted cover, weatherproof type, used for all non explosion proof applications; The "- T" is a threaded cover and explosion-proof type, which must be selected for all explosion-proof applications. Input "I" as 4-20mA, 4-12mA, or 12-20mA split range, with an impedance of 170 Ω; The 'H' has a split range of 10-50mA, 10-30mA, or 30-50mA, with an impedance of 27 Ω. Output code 2 is 20-100kPa, 3-15psi, 0.2-1.0bar; Code 3 is 40-200kPa, 6-30psi, 0.4-2.0bar or 3-27psi; Code 7 is 7-125kPa, 1-18psi, 0.07-1.3bar; Code 8 is 7-220kPa, 1-32psi, 0.07-2.2bar. When used for executing mechanisms, code 7 or code 8 are more common. The positive effect is an increase in input and an increase in output; The reaction is an increase in input and a decrease in output, and replacement must be consistent with the direction of valve failure safety.

The optional components also affect the replacement: - J is the overall explosion-proof junction box, - M is the 1/2NPT before the micro junction box, - P is the 1/2NPT after the micro junction box, - R is the adjustable filter pressure regulator without a gauge, and - S is the supply/output pressure gauge. Note that - M and - P cannot be used for - T casing; PG11 horn type cable connection cannot be used for electrical classification of CS-E/CD-A and CS-E/FD-A. If the original equipment comes with customer labels, special junction boxes, or split range inputs, the data card and AS code should be recorded before replacement to avoid new parts being unable to be wired or having incorrect addresses.

The installation location and gas source are the primary sources of zero drift

The E69F adopts an ammeter type motor, with a large gap between the coil and the housing. Corrosion and dust caused by normal atmospheric changes are not easily trapped in the mechanism, making it more resistant to dirt than voice coil instruments. But it is still sensitive to installation posture: it is calibrated for vertical installation at the factory, and if installed horizontally or obliquely on site, a maximum 5-degree angle change can cause a zero offset of 0.25% of the range. The safest approach is to calibrate the zero position at the actual installation location, rather than adjusting it on the experimental bench and then installing it. The installation surface should be able to withstand weight, with E69F weighing approximately 2.3kg (5lb). When fixing it on the valve yoke or pipeline, extra stress should be avoided.

The quality of the gas source directly affects the stability of the output. The supply pressure must be at least 20kPa (3psi, 0.2bar) higher than the maximum output signal pressure, and the air should be free of oil, dust, and water, in accordance with IEC 654-2. When the nominal supply pressure is 140kPa/20psi/1.4bar, the working range is 130 to 160kPa; When the nominal pressure is 240kPa/35psi/2.4bar, the working range is 225 to 260kPa. Output code 2 consumes approximately 0.50m ³/h (0.30scfm) of gas; At a supply pressure of 140kPa, codes 3, 7, and 8 have a flow rate of approximately 1.3m ³/h (0.75scfm), and at a supply pressure of 240kPa, they have a flow rate of approximately 1.7m ³/h (1.0scfm). If the on-site gas source contains oil and water, it is recommended to install a filter pressure reducer; -The R option is an adjustable filter pressure regulator without a gauge. When monitoring the supply pressure and output, select the - S pressure gauge. The air port is 1/4NPT, the electrical port is a 1/2-inch conduit connector, and the internal leads are 0.5m, 1.00mm ² (18AWG) twisted pair.

Zero position, range, and performance troubleshooting

Zero position adjustment can be done externally using a screwdriver; Adjust the range to internal wrench adjustment. On site, if there is a situation where the output is not 3psi when inputting 4mA, check the zero position first. If there is a situation where the output is less than 15psi when inputting 20mA, check the range and supply pressure first. The zero drift caused by changes in supply pressure is less than 0.04% of the range/kPa (0.25%/psi). If the supply pressure fluctuates greatly, the output will drift accordingly. The ambient temperature varies by 28 ℃ (50 ° F) within the working range of 0 to 60 ℃, with zero and range offsets not exceeding ± 1.0% of the range; The environmental limit is -40 to+80 ℃, and the humidity is 0 to 100% without condensation. Tilt at 5 degrees with a maximum zero drift of 0.25% range, which can be eliminated by calibration at the actual position. When the impact is 300m/s ² (30g), the maximum zero drift range is 0.5%. The vibration and impact effects are suppressed by rigid feedback flexible parts and low-quality components, but the converter should still be avoided from being installed on pipelines with strong vibration on site.