Choose the mounting location of the sensor, the isolator/barrier unit and the indicating transmitter so that they are protected from sudden impact and friction. The maximum distance between the isolator/barrier and the indicating transmitter STR is 30 m (98 ft).
| CAUTION If any of the system parts are affected by a sudden impact, power off immediately and have the system checked by trained Vaisala service personnel before it is used again. |
The following figures describe the electrical connections for PR‑23‑…‑IA/‑CI/‑JI/‑RI and the electrical connections for PR‑23‑…‑IF.
In the United States, installation must be in accordance with the applicable requirements of ANSI/ISA RP12.6 and the national electrical code (ANSI/NFPA 70). In Canada, installation must be in accordance with the applicable requirements of Canadian electrical code part I C22.2.1 section 18 and appendix F. Associated Apparatus manufacturer’s installation drawing shall be followed when installing this equipment.
Ex ia is defined as intrinsically safe. The intrinsic safety concept allows the interconnection of 2 intrinsically safe devices. FM approved and CSA certified entity parameters are not specifically examined in combination as a system when:
- Uo or Voc or Vt <= Vmax
- Io or Isc or It <= Imax
- Ca or Co >= Ci + Ccable
- La or Lo >= Li + Lcable, Po < Pi
| CAUTION Control equipment connected to the Associated Apparatus shall not use or generate more than 250 Vrms or V DC. Use supply wires suitable for 5 K above surrounding environment. |
For Division 1 installations, the configuration of Associated Apparatus shall be FM Approved/CSA Certified under Entity Concept.
Cables for intrinsically safe installation
The cables that connect the isolator unit to the indicating transmitter STR and the sensor are the following:
- 10 m (33 ft) cable, part number PR‑8230‑010, connecting the indicating transmitter STR and the isolator unit. The maximum cable length is 30 m (98 ft).
- 10 m (33 ft) power cable, part number PR‑8250‑010, connecting the indicating transmitter STR and the isolator unit, part number PR‑8250‑010. The maximum length is 30 m (98 ft).
- The intrinsically safe cable between isolator unit and sensor, part PR‑8260‑xxx, where xxx is the cable length in meters. The maximum length is 200 m (656 ft). For cable connections, see Intrinsically safe wiring, PR‑23‑…‑IA/‑CI/‑JI/‑RI according to WRG‑362 and Isolator unit wiring.
The maximum combined length of the cables is 230 m (755 ft).
| The isolator unit can use an optional external +24 V DC power supply instead of the +24 V DC power supply from the transmitter. +24 V DC is connected to terminals 13 and 14. If +24 V DC is used, the PR‑8250 power cable is not used at all. |