Ametek Crystal ATMi [ATMi-3M] Intrinsically Safe Temperature Module without Accessories, 10ft (3m) Cable Length. The Crystal ATMi intrinsically safe temperature modules, with flexible cable lengths, offer the functionality and flexibility to read up to 2 temperature inputs with a single HPC50 calibrator. In addition to the two installed pressure modules in the HPC50 Series, two ATMi temperature modules can be connected to the device. This provides the flexibility to read pressure with ambient and process temperature in the same instrument.