KROHNE CORIMASS E P MFM 2081 EEx EN - Manual (Page 4)

4 Additional Instruction for Ex version MFM 2081 / 3081
US-American Approvals
FM Class I, II & III Div. 1
Group A,B,C,D,E,F,G
MFM 2081 K/F
MFM 3081 K/F
J.I.4B8A1.AX
FM Class I, II & III Div. 2
Group A,B,C,D,E,F,G MFM 2081 K/F
MFM 3081 K/F J.I.4B7A7.AX
1.1 Description of the Transducer
The transducer MFS 2000-EEx and MFS 3000-EEx are intrinsically safe units and contains
three separated safe circuits. These are:
• ?Driver Circuit
•
?Sensor Circuit
• ?PT100 Circuit
The cables of these circuits are fed through the transducer housing via a special seal. There
are various transducer sizes available with different end connection options. Although
standard and EEx transducers appear the same, in fact the EEx version has a longer
converter mount (neck) and also contains specific clamping diodes fitted across the driver
coil. Therefore, it is essential to avoid using a standard converter with EEx transducer and
vice versa.
In order to fulfil the Ex certification requirements, it is absolutely necessary to comply with
the technical data. The maximum allowed process temperatures are:
MFS 3000 / E meter 200°C
MFS 2000 / P meter 200°C
MFS 2000 / P meter high temperature option, 60ºC
environmental temperature 240°C
MFS 2000 / P meter high temperature option, 55ºC
environmental temperature 255°C
1.2 Description of the Converter
The Ex converter is available in two different versions:
The ‘de’ version
The electronics are placed in a pressure tight section of the converter housing, protection
class ‘d’, while the termination compartment is not pressure tight. The converter housing
may be fitted with different cable glands such as NPT, PG16 or NPF glands for the mains
supply and the input/output cables. The protection class of the termination compartment
in ‘e’.
The ‘d’ version
The electronics as well as the termination compartment are placed in a pressure tight
housing. The termination compartment is not fitted with any gland for the mains supply or
the input/output cables. The customer is responsible for fitting an Ex approved cable gland
into the PG16 thread of the housing. There are various suppliers for such cable glands on
the market. The protection class of the termination compartment is ‘d’.