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TU551-CS31, CS31 bus terminal unit, 24 V DC, screw terminals
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TU552-CS31, CS31 bus terminal unit, 24 V DC, spring terminals
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TU552-CS31-XC, CS31 bus terminal unit, 24 V DC, spring terminals, XC version
1
I/O bus (10 pins, female) to connect other terminal units
2a
Plug (2 25 pins) to connect the inserted I/O modules
2b
Plug (2 19 pins) to connect the inserted I/O modules
3
With a screwdriver inserted in this place, the terminal unit and the adjacent terminal unit can be shoved from each other
4
2 holes for wall mounting
5
CS31 bus interface
6
30 terminals for signals and process supply voltage
7
DIN rail
PIN assignment for bus interface
 |
R1 |
Resistor + (end-of-line) |
|
R2 |
Resistor - (end-of-line) |
|
|
B1 |
CS31 bus + |
|
|
B2 |
CS31 bus - |
|
|
FE |
Functional earth |
|
|
B1 |
CS31 bus + |
|
|
B2 |
CS31 bus - |
|
|
FE |
Functional earth |
|
|
UP |
24 V DC process voltage |
|
|
ZP |
0 V process voltage |
The CS31 communication interface modules plug into the terminal unit. When properly plugged-in, they are secured with two mechanical locks. All the connections are established via the terminal unit, which allows removal and replacement of the CS31 communication interface modules without disturbing the wiring at the terminal unit.
The terminal units TU551-CS31 and TU552-CS31 are specifically designed for use with S500 CS31 communication interface modules that incorporate only 24 V DC inputs/outputs or interface signals.
XC version
XC = eXtreme Conditions
Extreme conditions
Extreme conditions
Terminal units for use in extreme ambient conditions have no 
sign for XC version.
The figure 4 in the Part no. 1SAP4... (label) identifies the XC version.
Terminals
|
Screw terminals |
Spring terminals |
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|---|---|---|---|---|---|
|
Conductor |
 |
Screwdriver |
Conductor |
 |
Screwdriver (opens terminal) |
The terminals 1.8 ... 4.8 and 1.9 ... 4.9 are electrically interconnected within the terminal unit.
The terminals always have the same assignment, irrespective of the inserted module:
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Terminals 1.8 ... 4.8: process voltage UP = +24 V DC
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Terminals 1.9 ... 4.9: process voltage ZP = 0 V
The assignment of the other terminals depends on the inserted CS31 bus module.
The supply voltage of 24 V DC for the module's circuitry comes from ZP and UP.