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TU517, terminal unit, 24 V DC, screw terminals
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TU518, terminal unit, 24 V DC, spring terminals
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TU518-XC, terminal unit, 24 V DC, spring terminals, XC version
1
I/O bus (10 pins, female) to connect the first terminal unit
2a
Plug (2 25 pins) to connect the inserted communication interface module
2b
Plug (2 19 pins) to connect the inserted communication interface module
3
With a screwdriver, inserted in this place, the terminal unit and the adjacent I/O terminal unit can be shoved from each other
4
2 holes for wall mounting
5
10 terminals for connection with the bus system
6
30 terminals for signals and process supply voltages (UP and UP3)
7
DIN rail
The 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 communication interface modules without disturbing the wiring at the terminal unit.
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 |
||||
|---|---|---|---|---|---|
|
Conductor |
 |
Screwdriver |
Conductor |
 |
Screwdriver (opens terminal) |
The terminals 2.8, 3.8, 2.9, 3.9 and 4.9 are electrically interconnected within the terminal unit.
The terminals always have the same assignment, irrespective of the inserted communication interface module:
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Terminals 2.8 and 3.8: process supply voltage UP = +24 V DC
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Terminal 4.8: process supply voltage UP3 = +24 V DC
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Terminals 2.9, 3.9 and 4.9: process supply voltage ZP = 0 V
The assignment of the other terminals depends on the inserted communication interface module (see communication interface modules for CANopen and PROFIBUS).