Barksdale BTS3000 Electronic Dual Temperature Switch, IO-Link

An electronic temperature switch with display and probe lengths from 17 mm to 650 mm

The Barksdale BTS3000 is an electronic temperature switch with a Pt100 Class A sensor to DIN/IEC 60751, a 4-digit red LED display and one or two programmable switch points. It measures -22 to 284 F (-30 to 140 C) with accuracy under plus or minus 0.5 percent of full scale at 25 C and repeatability of plus or minus 0.1 percent, and it adds an optional 4-20 mA output and an optional IO-Link interface. It replaces bimetal and capillary switches where the trip point needs to be visible and adjustable without opening anything.

Barksdale lists machine tools, hydraulic and pneumatic systems, injection moulding machines, cooling monitoring circuits, lubrication systems, construction machinery and the automobile industry as applications. The display and M12 connection rotate by 320 degrees and settings are made with three push-buttons.

Technical specifications

Probe lengths, connections and ordering code

The datasheet example is BTS3 8 E V M 2.00Z 1: series, output code, process connection, seal, M12 connection, sensor length and temperature range. Process connections are 1/4 inch NPT male (N), 1/2 inch NPT male (consult factory), 7/16-20 UNF SAE-4 male (E) and G1/4 male (G), with G1/2 male on request. Probe lengths are 17, 25, 50, 100, 300 and 650 mm for G threads and 0.7, 2, 4, 6 and 12 inch for NPT and UNF threads, with custom lengths possible. The datasheet notes that at probe lengths over 300 mm the probe should be kept out of the direct path of flowing media. Seals are FKM as standard, EPDM or FFKM (consult factory); units with NPT threads need seal code X (no seal). The temperature range code is 1 for 0 to 100 C, 2 for -30 to 140 C, 3 for 32 to 210 F and 4 for -22 to 280 F.

Output codes are 1 dual switch point; 2 single switch point plus 4-20 mA (0-10 V selectable); 3 single switch point plus 0-10 V; 4 dual switch point plus 4-20 mA; 5 dual switch point plus 0-10 V; 6 dual switch points with relay outputs (one NC, one NO, not UL approved); 7 IO-Link with dual switch point; and 8 IO-Link with dual switch point plus 4-20 mA. IO-Link codes carry no UL approval.

Electrical data and accessories

Supply is 15 to 28 V DC with reverse-polarity protection and about 50 mA without load (80 mA on output code 6). Switching outputs are PNP, with NPN field selectable on IO-Link units, up to 500 mA (250 mA IO-Link) at 100 Hz with a delay of 0.0 to 50.0 s. The relay option is 1 A, 60 V, 30 VA. The time constant is about 40 s. The IO-Link interface is COM2 at 38.4 kBaud, revision 1.1, IEC 61131-9, minimum cycle time 2.5 ms. Accessories include M12 4-pin and 5-pin connectors and 1 m shielded cables, and brass or 316 stainless steel thermowells for the 2, 4 and 6 inch probes (the thermowell option is for 1/2 inch NPTF only; consult the factory).

Typical duties on machines and fluid systems

On hydraulic power units, lubrication systems and cooling circuits the BTS3000 is usually installed where an oil or coolant temperature must be held within a band or must trigger an action when it moves outside that band. One switch point can start a cooler or a heater while the second raises a warning or stops the machine, and window mode lets a single output indicate whether the temperature sits inside an acceptable range. On injection moulding machines and machine tools the same approach protects hydraulics and spindle cooling. Where the machine controller also needs a continuous value for trending or closed-loop control, the analogue output variants send the measured temperature alongside the switching signal.

Integration with PLCs and IO-Link masters

Conventional variants are wired to PLC digital inputs for the switch points and to an analogue input card for the 4-20 mA or 0-10 V signal. IO-Link variants connect to an IO-Link master, which carries the measured value, switch status and parameter settings over a single standard M12 cable. This makes it possible to store switch point settings in the control system and restore them when a unit is exchanged, and it reduces the number of separate signal cores between the machine and the cabinet. When planning a project, keep in mind that the IO-Link codes and the relay option do not carry the UL approval, so check the approval requirement of the machine before choosing the output code.

Selecting probe length and installation position

The probe should reach far enough into the fluid to measure the bulk temperature rather than the temperature of the pipe wall or a dead zone in a tank. Short probes suit compact hydraulic manifolds, while longer probes suit reservoirs and larger pipes; for the longest lengths the datasheet guidance about keeping the probe out of direct flow should be followed. Because the time constant is in the order of tens of seconds, the switch is best suited to monitoring and protection of thermal processes that change gradually, and switching delays should be set with this response in mind. Where the process must remain closed during service, a thermowell from the listed accessory range may be considered for the probe lengths it covers.

Machines and plants in Oman and the GCC

Hydraulic and lubrication systems in Oman and across the GCC frequently run in hot plant rooms or outdoors on mobile and construction machinery. The electronics operating range listed above should be compared with the real ambient temperature at the mounting point, and units should be shielded from direct sun where possible. The enclosure ratings support installation in dusty or wet areas, provided the M12 connection is fully made up with a suitable mating cable.

Installation and what to confirm before ordering

Wetted parts are 304 stainless steel with maximum pressure of 2,900 psi (200 bar). The enclosure is Type 4X (IP65) / Type 6 (IP67), 1.6 inch diameter by 4.4 inch without plug and sensor, and weight is about 0.4 lb (200 g). Electronics operate at 14 to 140 F and storage is -22 to 176 F. The datasheet lists cULus (E302981) for output options 1 to 5 only. Confirm the temperature range code, probe length against the pipe or tank, thread, whether a thermowell is needed, the output code and the mating M12 cable. The attached file is the two-page datasheet (bulletin T0032-F). More sensors are in temperature instrumentation; send the full code for a quotation.