Siemens SIMATIC 505 - Wiring the Input Connectors; Input Connector Wiring

Installlation
2-8
SIMATIC 505–2556 Installation and Operation Guide
Configuring the Module (continued)
Thermocouple input signals are accepted through a fixed wire press in
connector block located on the front of the module. Consult the
thermocouple manufacturer ’ s recommendations for selecting the input wire
type and size. The front connector accepts wire from 18 to 30 A WG.
The SIMA TIC 505–2556 uses a fixed connector to terminate field wiring.
This is used because the chemistry of a removable connector may have an
adverse effect on the accuracy of the measurement. Siemens has carefully
selected a connector that minimizes this effect.
T o assign an input to a specific channel, locate the appropriate channel
position on the connector as shown in the following figure. W ires must be
inserted by pressing the wire into the connector receptacle. T o remove the
wire use a small screwdriver to depress the connector lever . Then remove
the thermocouple wire.
On each channel input the positive lead for the thermocouple is attached to
the Cn+ terminal and the negative lead is attached to the Cn– terminal. If a
shield is used it is attached at the Gn terminal. The ”red” lead is always the
negative lead for thermocouples.
Figure 2-3 Input Connector W iring
W iring the Input
Connectors