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

9.13

Zener Diode Boards

Part No. 6ES7650-1BB51-0XX0 or 6ES7650-1BB50-0XX0 and 6ES7650-1BC51-
0XX0 or 6ES7650-1BC50-0XX0
9.13.1

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 Module (6ES7 336-1HE00-0AB0, E-Stand 4 or higher).
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.
9.13.2

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. Because the FAI may only be
used in current mode when used in the Safety mode, 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 9–9 shows a simplified schematic.
Marshalled Termination Assemblies for ET200M Remote I/O Modules
A5E00482820-12
6-Channel F Analog Input MTA
101