Yokogawa RAMC - Manual (Page 93)

<10. EXPLOSION-PROTECTED TYPE INSTRUMENTS>
10-1
IM 01R01B02-00E-E 10th edition January 01, 2013 -00 All Rights Reserved. Copyright © 2003, Rota Yokogawa
10. Explosion-protected Type Instruments
10.1 General
10.1.1 Intrinsic safety
To ensure intrinsic safety it is not permitted to repair or to modify the electronic transmitter, the display, the
limit switches or the calibration EEPROM.
The electronic transmitters type -E /KS1, -H /KS1, -J /KS1, -E /KS2, -H /KS2 , -J /KS2, -E /KS3, -H /KS3, -J /KS3,
-E /ES1, -H /ES1, -J /ES1, -E /ES3, -H /ES3, -J /ES3, -E /ES2, -H /ES2 , -J /ES2, -E /FS1, -H /FS1, -J /FS1,
-E /NS1, -H /NS1, -E /CS1, -H /CS1, -J /CS1, -E /SS1, -H /SS1, as well as the limit switches option /Kx with
option /KS1, /KS2, /KS3, /FS1, /CS1, /NS1, /SS1 are intrinsically safe devices.
Power supply for the electronic transmitter and transmitter relay for the limit switches are associated apparatus
and should be installed outside any hazardous area.
The electronic transmitter must be connected to an intrinsically safe, certified power supply with a maximum
voltage and output power below the maximum values of the electronic transmitter (refer to Technical data, in the
concerning chapters). The combined internal inductance and capacity of the electronic transmitter and connecting
cables must be less than the permitted external inductance and capacity of the power supply.
Accordingly, the limit switches have to be connected to intrinsically safe, certified isolating switching amplifiers.
The relevant maximum safety values must be heeded at all times.
Especially in the case of high fluid temperatures, heated metering tubes or heat radiation by heat tracing, make
sure that the temperature in the indicator housing does not exceed the permissible maximum ambient
temperature of the transmitter (refer to Technical data, chapter 9).
10.1.2 Flame proof
In the RAMC with option /KF1, /EF1, /NF1 the transmitter and the limit switches are mounted in a flame proof
housing.
Wait 2 minutes after switching power off before opening the cover.
The cover can only be opened after loosing the safety screw.
After closing the cover the safety screw must be fixed before switching power on.
The RAMC with option /KF1, /EF1, /NF1 shall be connected up via suitable cable glands and / or conduit
systems that satisfy the requirements of EN 50018 or 60079-1 sections 13.1 and 13.2 and for which a separate
test certificate is available. Cable glands and entry fittings (screwed conduit entries) as well as blanking plugs of
simple design may not be used. On connection of the RAMC /KF1, /EF1, /NF1 using a conduit entry approved
for the purpose, the associated sealing facility must be arranged directly on the housing.
Unused openings must be closed off as defined in EN 60079-1 section 11.9 (e.g. certified blanking elements).
The RAMC with option /KF1, /EF1, /NF1 shall be connected to the local equipollently grounding system.
Especially in the case of high fluid temperatures, heated metering tubes or heat radiation by heat tracing, make
sure that the temperature in the indicator housing does not exceed the permissible maximum ambient
temperature of the transmitter (refer to Technical data, chapter 9).
WARNING