Siemens 505-2557 Manual De Usuario
Advanced Function Programming
3-31
SIMATIC 505–2557 Installation and Operation Guide
3.10
Items Unique to the SIMATIC 505–2557 Module
Items unique to the SIMATIC 505–2557 RTD Input Module.
Open RTD Status Bits: WX55
Figure 3-18
Open RTD Status Bits
The bits returned in WX 55 indicate an open RTD for a particular channel.
Floating Inputs
If no RTD is connected to an input channel the value returned to the PLC is
unpredictable.
If no RTD is connected to an input channel the value returned to the PLC is
unpredictable.
The inputs on the SIMATIC 505–2557 are floating; that is there are no
internal pull up or pull down circuits to force the input to either a maximum
or minimum temperature value. Unused inputs therefore should be
terminated by shorting the V+ and G terminals together.
internal pull up or pull down circuits to force the input to either a maximum
or minimum temperature value. Unused inputs therefore should be
terminated by shorting the V+ and G terminals together.