Connecting The Field Wiring - Automation Direct DL405 User Manual

Connecting the Field Wiring

Wiring Guidelines Your company may have guidelines for wiring and cable installation. If so, you should
check those before you begin the installation. Here are some general things to
consider.
RTD – Resistance Use shielded RTDs whenever possible to minimize noise on the input signal.
Ground the shield wire at one end only. Connect the shield wire to the COM
Temperature
(common) terminal.
Detector
Lead Configuration for RTD Sensors
The suggested three-lead configuration shown below provides one lead to the CH+
terminal, one lead to the CH– terminal, and one lead to the COM (common) terminal.
Compensation circuitry nulls out the lead length for accurate temperature
measurements.
Some sensors have four leads. When making connections, do not connect the
second red lead to the CH+ input; leave that lead unconnected.
Do not use configurations having only one lead connected to each input (there is no
compensation and temperature readings will be inaccurate).
See Errata Sheet at the
beginning of this file.
There is a revised
drawing. The wire leads
colors were revised.
Ambient The F4–08RTD module has been designed to operate within the ambient
Variations in temperature range of 0_C to 60_C.
Temperature
Precision analog measurement with no long-term temperature drift is assured by a
chopper-stabilized programmable gain amplifier, ratiometric referencing, and
automatic offset and gain calibration.
S
Use the shortest wiring route whenever possible.
S
Use shielded wiring and ground the shield at the signal source. Do not
ground the shield at both the module and the source.
S
Don't run the signal wiring next to large motors, high current switches, or
transformers. This may cause noise problems.
S
Route the wiring through an approved cable housing to minimize the risk
of accidental damage. Check local and national codes to choose the
correct method for your application.
Wiring Connections For Typical RTD Sensor
Black
Black
Sensor
Red
Red (if applicable)
F4–08RTD 8-Channel RTD Input
To CH–
To COM
To CH+
No Connection
(if sensor has 4 leads, only
connect one lead to CH+)
9–7