Rockwell Automation T8841 Trusted 8 Channel RTD FTA - Manual (Page 8)

Trusted
TM
RTD FTA T8841
Issue 6 Nov 07 PD-T8841 8
Each RFTA temperature output is configurable for the following:
1. 4-20mA current source output.
2. 0-5V dc voltage source output.
The 4-20mA current source output is the preferred option. The 0-5V dc option provides an overall
operating range of 0-5V dc with a healthy field loop operating range of 1-5V dc.
RTD devices in the field are connected to the RTD FTA by cables terminated at eight 3-way
connectors (RTD1 to RTD8). The eight temperature outputs from the RFTA is via a 10-way connector
(IOIF). The dual 24V dc power supplies are connected to the RFTA via a 4- way connector (PWR).
2. System Functions
2.1. Zero, Gain & Linearisation
The RTD linearisation for each channel is controlled by two factory pre-set linearisation resistances,
RLIN1 and RLIN2. These values are dependent upon the zero and full scale settings required for that
channel. Each channel has provision for two separate link selectable values for both RLIN1 and
RLIN2.
The zero setting for each channel is controlled by the factory pre-set zero resistance, Rz. Each
channel has provision for two separate link selectable values for Rz.
The full scale setting for each channel is controlled by the factory pre-set gain resistor Rg. Each
channel has provision for four separate link selectable values for Rg.
3. Installation
The Trusted TM 8 Channel RTD FTA T8841 is designed to be mounted on either of the TS32 or TS35
DIN rails in the horizontal or vertical positions.
3.1. Cable Selection
The Trusted TM 8 Channel RTD FTA can connect direct to an Analogue Input Module using either
companion cables TC-211/212 or smart-slot cables TC-511/512. The Output can also be connected to
the Analogue Input module via a VFTA if necessary to be compatible with an existing installation,
where complete groups of channels can be wired to T8841 FTAs or other inputs as required.