IP Converter YT-940 Rotork YTC

The YT-940 is the flameproof I/P converter in the Rotork YTC range. Its aluminium enclosure is built to contain an internal ignition rather than to limit loop energy, which is the protection concept most Pakistani refinery and gas-processing standards apply when barriers are not part of the design. Rated Type 4X (FM) and IP66, coated in polyester powder, and weighing 2.5 kg, it is the heavier and more rugged of the two YTC converters — and the one that keeps working down to -40 °C, with a flameproof ambient limit of -40 to 85 °C at T5 and -40 to 75 °C at T6.

Electrically it is a straightforward 420 mA device with a maximum loop impedance of 313 Ω at 20 mA. Pneumatically it offers four standard/multi-range output bands and, unusually, four selectable supply-pressure bands running as high as 0.250.27 MPa — which matters when the converter has to be driven from a header that is not sitting at the usual 1.4 bar.

How the YT-940 differs from the YT-930

The conversion element is common to both models. Both take 420 mA DC, both offer the same set of output pressure ranges (0.020.1 MPa standard, plus 00.12, 0.040.2 and 0~0.23 MPa), both consume below 2 LPM and pass 70 LPM at 0.14 MPa, and both hold ±0.5% F.S. linearity and hysteresis, ±0.2% sensitivity and ±0.3% repeatability. The differences are in construction and rating:

Choose on area classification and installed wiring practice first. If the loop runs through a safety barrier and the site works to an intrinsic-safety regime, the YT-930 is the correct unit; if protection is by flameproof enclosure and gland, this is. Do not choose between them on output range — those are the same.

Specification

Refer to the certification section of the manufacturer’s literature for the exact flameproof gas group and temperature class approved for your area — the specification sheet points to section 2.6 rather than listing a single rating, because the approval varies by certifying body.

Typical application

The YT-940 belongs in the classified areas of oil & gas plant where the whole electrical installation is built around flameproof equipment and cable gland entries: gas compression skids, refinery process units, LPG and condensate handling. In those areas an intrinsically safe device would need a barrier and a separate cable schedule; the flameproof converter simply lands on the same G 1/2 conduit run as everything else around it.

The wide supply-pressure banding is the second reason it gets specified. On older cement and pipe manufacturing plant, instrument air headers are often run at a pressure chosen for tools rather than for instruments, and the ability to order the converter calibrated for a 0.220.24 or 0.250.27 MPa supply avoids adding another stage of regulation. As with the YT-930, a YT-200 air filter regulator mounts directly against the body with no interconnecting tube, and the output can be piped straight to a diaphragm actuator or to the input of a YT-1000R positioner.

Check the product catalog, or for more details visit the manufacturer’s website.