Emerson IP258 manual D13.0 SMART Interfaces - Compatibility D13.1 Introduction

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.

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