Installation
Model 2-Wire
35
5
5.4 Model 2-Wire
The 2-wire model provides a standard two-wire current loop output and USB communications.
5.4.1 Back Panel
The rear panel supports a 3-pin terminal for connecting the alarm output (AL) and the 4 to 20 mA current loop.
The polarity is indicated on the panel.
Figure 5-3: Rear Panel for 2-Wire Sensor and Emissivity Preset at 0.95
Table 5-1: Terminal Connections
Designation
Description
AL
alarm output
positive signal (4 to 20 mA)
and positive power supply
Θ
negative signal (4 to 20 mA)
and ground
Above the terminal there are two rotary switches (EMS) for emissivity setting. Emissivity is changeable in tenths
(left switch) and hundredths (right switch). The preset for the rotary switches at the factory default is 0.95. The
appendix lists typical emissivity values for common materials, see section 15.4
page 123.
The smallest adjustable emissivity is 0.10. In the switch positions below 0.10, the device enters the test mode and
provides the functions listed below.
Table 5-2: Test Modes
Emissivity Switch
Test Mode
0.01
Current output permanently provides 4 mA
0.02
Current output permanently provides 20 mA
0.03
Alarm relay permanently toggles between “open” and
“closed”
0.04
Current output provides internal case temperature
Scaling is fixed to -40 to 120°C (-40 to 248°F)
0.05
reserved
0.06
reserved
0.07
reserved
0.08
reserved
0.09
reserved
www.
.com
1.800.561.8187