Engineering notes
BMS temperature sensors: NTC, PT100 or PT1000
How NTC, PT100 and PT1000 differ on a DDC. Match the input type; do not buy by probe shape.
Three families on a BMS
NTC resistance falls as temperature rises — common for rooms, enough for offices and corridors. PT100 and PT1000 are platinum, more linear, common on pipes and ducts where a stable reading matters.
Many DDCs have a dedicated NTC input (10 kΩ, 20 kΩ curves). A PT1000 in an NTC input reads several degrees out — enough to open a chilled-water valve by mistake. “NTC 10K type II” is not “RTD PT1000”.
PT100 often needs an RTD module or a 4–20 mA transmitter. Some panels read PT1000 directly. Two-wire NTC is enough for a short room run; PT100 on a long workshop run wants three or four wires. Choosing sensors