Control schematic for wiring of intrinsically safe positioner for US & Canada (Sheet 2 of 4)
Hazardous location
Class I, DIV 1, Groups A,B,C,D
Class II, DIV 1, Groups E,F,G
Rosemount® 275 HART®
Communicator-note 4
Magnum
switch
option
SmartCal Series
positioner
Associated apparatus
(Intrinsic safety barriers)
MTL model 707 or 787S
Note 1
MTL model 7087 used for
digital ON/OFF inputs
Control
equipment
Note 2
4-20 mA
Analog
output
Nonhazardous location
1. Associated apparatus manufacturer’s installation drawing must be followed when installing this
equipment.
2. Control equipment connected to associated apparatus must not use or generate more than 250 V.
3. To maintain intrinsic safety, each field wiring pair (4-20 mA and analog output) must be run in
separate cables or separate shields connected to intrinsically safe (associated apparatus) ground.
4. Rosemount® 275 HART® Communicator is NOT FMRC approved for use in Class II and III
Hazardous Locations.
5. For Class II and III locations where rigid metal conduit is not used, seal SmartCal cable entries
against dust and fibers using an appropriate NRTL listed cable gland fitting.
6. Installation should be in accordance with ANSI/ISA RP12.6 and the National Electrical Code
(ANSI/ NFPA 70).
Note 3
Maximum allowable field wiring capacitance and inductance
Hazardous location & configuration
Maximum allowable Maximum allowable
field wiring
field wiring
capacitance
inductance
GP A or B location W/Communicator
30 nF
4,0 mH
GP C,D,E,F,G location W/Communicator
230 nF
16 mH
GP A OR B location W/OUT Communicator*
100 nF
4,0 mH
GP C,D,E,F,G location W/OUT Communicator*
300 nF
16 mH
* Rosemount® 275 HART® Communicator not used or used only on the INPUT side of associated
apparatus.
page 38
AVID SmartCal valve positioner
Installation & operating instructions
