K121 supports input signals from Cu50, Cu100, Pt100, Pt500, Pt1000, Ni100, Ni120, Ni1000, TC J, K, R, S, T, B, E, N, L, potentiometer, voltage signals with ± 30 V and ± 150 mV scales and current (± 24 mA). The instrument also acquires potentiometer input with resistance between 500 Ω and 10 K Ω and resistances up to 1760 Ω. K121 features a reduced response time of only 140 ms for current and voltage input and less than 620 ms for other inputs. The accuracy class is 0.1% and the measurement conversion to 16 bit. K121 is ATEX certified II 3G Ex nA IIC T4 Gc X (gas) and II 3D Ex tc IIIC T135°C Dc X (dust).