Transmitter LKM121 for thermocouples and resistance sensors
The LKM121 is a digital, programmable transmitter with galvanic isolation between input and output for mounting in the type B connection head. It can be set for different thermocouples according to DIN EN 60584 and DIN 43710 as well as for different resistance sensors according to DIN EN 60751. It converts the temperature-dependent measured variable of the sensor into a standard signal of 4...20mA or inversely 20...4mA. Lead resistances are compensated by means of a four-wire circuit. A three- or two-wire circuit can also be implemented. The temperature compensation for thermocouples is done in the transmitter itself. The transmitter is supplied configured to customer specifications. Subsequent changes to the sensor and measuring range can be made with our "Programming Kit for LKM120/121" and a PC. The required program is available free of charge in the "Downloads" tab.
For a small correction, an offset can be set by software.
The selection menu is available for configuration.
When entering your individual measuring range, please note the measuring range of the selected sensor. These can be found in the technical data. The minimum span for resistance sensors is 20°C and for thermocouples 200°C.
Likewise a delivery for other sensors, which are not listed in the selection menu, can take place.
| Thermocouple | Specification range in °C |
|---|---|
| Type B | 0 – 1820 |
| Type E | -200 – 1000 |
| Type J | -210 – 1200 |
| Type K | -200 – 1372 |
| Type L | -200 – 800 |
| Type N | -200 – 1300 |
| Type R | -50 – 1768 |
| Type S | -50 – 1768 |
| Type T | -200 – 400 |
| Pt100 | -250 – 650 |
| Pt1000 | -200 – 200 |
| Ni100 | -60 – 250 |
| Ni1000 | -60 – 120 |
| Feature | Value | Remark |
|---|---|---|
| Input | Pt100 / 500 / 1000 / Ni100 | 2-, 3-, 4-wire connection |
| J, K, R, S, T, B, E, N | Specification limits see table 2 & 3 | |
| Potentiometer | 0 – 1700 Ω | |
| Resistance | 0 – 1760 Ω | |
| Voltage | -150 – 150 mV | |
| Minimum span | 20 K / 100 K | RTD / TC |
| Measurement current | 0.4 mA | RTD |
| Zero point | programmable | |
| Response time | 0.6 s | |
| Linearity error | < 0.1 % | FS |
| Loop voltage | 7 – 30 VDC | reverse polarity protected |
| Isolation voltage | 1500 V | |
| Lead resistance | max. 25 Ω | RTD / per lead |
| Resolution | > 13 bit | |
| Load resistor | < 900 Ω | at 24 V |
| Sampling rate | 300 ms | rise time (10 – 90%) 650 ms |
| Output | 4 – 20 mA | |
| Sensor break | > 20 mA | programmable |
| Short circuit | < 4 mA | programmable |
| Terminal type | Spring terminals | 0.2 – 2.5 mm² |
| Enclosure | Nylon, black | |
| Temperature coefficient | < 100 ppm | |
| Operating temperature | -40 – 85 °C | |
| Dimension | 43.3 × 20 mm | D x H |
| Weight | 32 g | |
| Temperature compensation | internal | external possible |
| EMC | EN 61326-1 EN 61326-2-3 |
emission and immunity |
| Thermocouple | Specification range in °C |
|---|---|
| Pt500 | -200 – 650 |
| Ni120 | -80 – 260 |
| CU50 | -180 – 200 |
| CU100 | -180 – 200 |
Documents
| Document | Format | Language(s) |
|---|---|---|
| Datasheet – LKM121 Technical specification |
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| Operating Instructions – LKM121 Installation and operating manual |
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Software
| Program / Package | Format | Language(s) |
|---|---|---|
| Service Program – LKM120/121 Parameterization Software |
ZIP |  |
| Program – AnalogToTemperatur Conversion of analog output values (mA or V) to temperature |
ZIP | |
