Appendix A: Safety Instructions – Ver. 1.00
30
A.2
System Description:
A Rheonik Coriolis mass flow meter system for hazardous areas consists of a mass flow sensor
RHM and a transmitter RHE with built in barrier or of a mass flow sensor RHM, a dedicated barrier
EZB and a transmitter RHE without barrier.
The mass flow sensor RHM is intrinsically safe and can – depending on the individual certification
– be mounted in zone 0, zone 1 or zone 2. For the American market versions for div. 1 and for div
2 are available.
The RHE26/27 are associated equipment and contain the barriers for the RHM to be connected.
The transmitters RHE26 and RHE27 must be mounted in ordinary (non-hazardous) location only.
A.3
Electrical Safety Limits
Power supply and I/O:
Signal
Terminals
Type
Nominal Voltage
Max. Voltage
Um
AC supply
23, 24
Supply
90 – 250V AC
250V
250V
DC supply
20,21
Supply
10 – 28V
30V
250V
Supply for
analog out
50, 57
Supply out
24V
30V*)
250V
Digital Out 31 - 34
Out
24V
30V**)
250V
Analog Out 51 - 56
Out
24V
30V
250V
Digital In
35, 36
In
24V
30V
250V
RS485
70, 71
Interface
70 to 71: ±5V
30V to PE***)
250V
USB
(Connector) Interface
5V
5V
250V
*) A short circuit to any voltage between 0V and 30V should be avoided, but will not damage the
output. The current is internally limited by a self-resetting poly-fuse.
**) A short circuit to any voltage between 0V and 30V should be avoided, but will not damage
the output.
***) The nominal signal Voltage between 70 and 71 is 3.3V. The interface is floating but clamped
to PE with a clamping voltage of 30V.
Applied voltages above the maximum voltage may damage the corresponding input or output
but will not affect the safety on the connection to the IS RHM or the IS pressure sensor.
Voltages above the Um values must be avoided.
