STS SENSOREN TRANSMITTER SYSTEME · LEVEL MEASUREMENT TRANSMITTERS

STS ATM/N/IS FM/FM-C Certified Level Transmitter

STS manufacturer's similar ATM.1ST/N/Ex photograph, not the actual ATM/N/IS order code.
STS manufacturer’s similar ATM.1ST/N/Ex photograph, not the actual ATM/N/IS order code.

Submersible liquid-level transmitter with 1–250 mH₂O range, accuracy options ±0.50/±0.25/±0.10% FS, −5 to +80°C ambient and liquid temperature, 4–20 mA output, and titanium/stainless steel variants. Manufacturer’s FM and FM-C documents apply only to approved order codes.

Original manufacturer technical documentation

STS ATM/N/IS model specifications and downloads →.

Important hazardous-area limitation: FM/FM-C approval is not equivalent to an ATEX or IECEx certificate. Any certificate listed by the manufacturer must be matched to the actual variant’s approval number, gas/dust class, wiring/circuit barriers and marking. Merely sharing an /IS suffix or product photograph does not establish universal approval.

FM-approved installation limits (STS operating/safety instruction 10.00.0410.B, 02/2016): For ATM/N/IS Series 84, the manufacturer’s FM intrinsically safe installation schedule specifies temperature class T4 and environmental and medium temperatures −5 to +50°C. This is more restrictive than the −5 to +80°C ordinary product specification above; do not use the general operating range as the FM hazardous-area limit. Entity input maxima: Vmax 30 V, Imax 100 mA, Pi 1 W; input capacitance Ci 10 nF + 0.12 nF per metre of integral cable, inductance Li 0.1 mH + 0.001 mH per metre of integral cable. Approved associated apparatus and cable-length allowances must be checked for the actual installation. Official STS FM installation and safety instruction (PDF). Verify against the current unit label and applicable approval revision.

Document-revision conflict and order-code gate: STS datasheet 10.80.0532.A (June 2019), order-type 34, lists temperature option codes 3 (T6, −5…+50°C), 4 (T4, ambient −5…+80°C, process −5…+50°C) and 5 (T4, ambient and process −5…+80°C). That is broader and differently classified than the 2016 FM operating instructions above. The conflicting documents must not be treated as interchangeable FM approval schedules: obtain the current FM/FM-C certificate and matched nameplate/order-code approval before specifying a hazardous-area temperature limit. For this family the 2019 datasheet cites FM 3027351 and FM-C 3027351C. Official ATM/N/IS ordering table (page 5).