Description

The RTD module supplies a small current to each RTD connected to the

module inputs (up to 8 input channels). The module provides on-board

scaling and converts RTD input to temperature (°C, °F) or reports resistance

input in ohms.

Each input channel is individually configurable for a specific input device.

Broken sensor detection (open- or short-circuit) is provided for each input

channel. In addition, the module provides indication if the input signal is

out-of-range. For more detail on module functionality, refer to the subsection

entitled System Overview later in this chapter.

General Diagnostic Features

The RTD module contains diagnostic features that can be used to help you

identify the source of problems that may occur during power up or during

normal channel operation. These power-up and channel diagnostics are

explained in Chapter 6. Module Diagnostics and Troubleshooting.

The RTD module communicates to the SLC 500 processor through the

parallel backplane interface and receives +5V dc and +24V dc power from the

SLC 500 power supply through the backplane. No external power supply is

required. You may install as many RTD modules in your system as the power

supply can support, as shown in the illustration below.