Zener Diode Boards; Description; Operation - Siemens ET 200M Manual

6-Channel F Analog Input HART MTA
10.12

Zener Diode Boards

Part No. 6ES7650-1BB51-0XX0 or 6ES7650-1BB50-0XX0 and 6ES7650-1BC51-
0XX0 or 6ES7650-1BC50-0XX0
10.12.1

Description

This section contains installation information and requirements for the two Siemens
Zener Diode Boards. The 6.2 VDC (6ES7650-1BC51-0XX0 or 6ES7650-1BC50-
0XX0 ) and the 5.6 VDC (6ES7650-1BB51-0XX0 or 6ES7650-1BB50-0XX0) are
used on the ET200M Marshalled Termination Assembly (MTA) (6ES7650-1AH51-
5XX0 or 6ES7650-1AH50-5XX0) designed to interface with the Siemens ET 200M
6-Channel F Analog Input HART Module (6ES7 336-4GE00-0AB0).
Note: The two part numbers for the 5.6 V Diode Board are interchangeable. The
two part numbers for the 6.2 V Diode Board are also interchangeable. Do not
interchange 5.6 V Diode Boards with 6.2 V Diode Boards.
10.12.2

Operation

The 6.2 VDC and the 5.6 VDC Zener Diode Board allows proper operation of the 6
Channel Failsafe Analog Input Module with the MTA. Diodes are placed in parallel
with the module inputs. One diode spans one channel on one module; therefore,
one diode board handles one module. The diodes are normally not conducting but
when a module or the interconnecting cable is removed; the diodes conduct and
keep the current constant for the other module. In a redundant system none of the
diodes normally conducts, but in a non-redundant system one set is always
conducting. Figure 10–5 shows a simplified schematic.
126
Marshalled Termination Assemblies for ET200M Remote I/O Modules
A5E00482820-12