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D13.0 SMART Interfaces – Compatibility
D13.1 Introduction
The MOBREY MSM400 SMART slurry monitoring system unit uses the HART digital communications
protocol.
This was originally developed by Rosemount Inc. in USA, and uses Bell 202 Frequency Shift Key
signalling on top of a 2 wire DC loop supply. The MOBREY MSM400 system conforms to Revision 5.1
of the HART protocol.
Various other manufacturers use this same HART protocol and produce sensor equipment that can be
attached to 4-20mA or digital loops. Similarly there are other hand held communicators that use the
HART protocol to interrogate transmitters in such loops. Not all manufacturers’ equipment conforms to
the Revision 5.3 of the protocol.
At present the major SMART communicators working to a HART protocol are
MOBREY –CK1 and –CK2
HART Communicator Model 275 manufactured by Rosemount
Rosemount Model 268
Measurement Technology MTL 611 and CNF 41
MOBREY H-View
This is a rapidly developing field, and the specification of these units is continually being updated. Each
updating produces better interoperability and user friendly operation. However, even equipment
conforming to the same Revision of the protocol from different manufacturers cannot be regarded as
compatible, because each sensor has a unique programme structure.
D.13.2Transmitters recognised by the MOBREY SMART Communicators
The MOBREY-CK1 and –CK2 SMART Communicators can identify and interrogate all variants of the
MLT100 and MSP100 ultrasonic level transmitters and MSM400 slurry monitors.
If a MOBREY SMART Communicator is connected to a loop with another type of control unit, for e
example the Rosemount 1151 pressure control unit, it will record the presence of an “Unknown
instrument”. Various parameters can be read and a limited set of common parameters can be changed.
D.13.3Use of multiple SMART Communicators
The HART SMART protocol allows two SMART digital communicators to be active on the same loop
at once. Only one of these can be a hand held communicator (known as “Secondary Master”) such as
the MOBREY-CK1 or the Rosemount 275 : the second must be a permanent monitoring system such as
MOBREY H-View (which is designated as a ”Primary Master”).
If two hand held communicators are connected to the same loop at the same time and both try to
communicate at once there will be a conflict in the messages and neither unit will function correctly.