Setra System 267MR - Manual (Page 8)

5
Diagram 7 Diagram 8
CONNECTION 9 pin D-sub Connector
+EXCITATION 4
-EXCITATION 9
PIN 4
30
Loop Supply Voltage (Vdc)
Operating
Range
9
Loop Resistance (Ohms)
0
Diagram 9
3.4 Current Output Untis – 9 pin D-sub Connector Electrical Termination
The Model 267 and 267MR is a two-wire loop-powered 4 to 20mA current out-
put unit (see Diagram 6). The current flows into +EXC. Pin 4 (+EXC) and returns
back to the power supply through Pin 9 (-EXC) (see Diagram 7). The power
supply must be a DC voltage source with a voltage range between 9 and 30
measured between Pin 4 and Pin 9 (-EXC). The unit is calibrated with a 24VDC
loop supply voltage and a 250 ohm load. The current output 9 pin
D-sub connector pin designations are shown in Diagram 8.
3.5 4-20 mA Circuit Diagram
Minimum Supply Voltage (VDC) = 9 + 0.02 x (resistance of receiver plus line)
Maximum Supply Voltage (VDC) = 30 + 0.004 x (resistance of receiver plus line).
If the current loop has a current limiter, the threshold should be adjusted to 35
mA minimum (see Diagram 9).
Loop Power Supply vs.
Loop Resistance for 4 to 20 mA Current Transducers
3.6 EMC Certification
This product complies with EN61326-1:2006 in accordance with EN61326-2-
3:2006 to be used in Controlled EM Immunity and Class B Emission environ-
ment. Special cautions must be take to fully meet EU EMC compliance:
1. Shielded cable must be used, and the shield must be tied to earth
ground (not power supply ground) on at least one end of the cable
shield/drain wire. The shield must be maintained all the way from sen-
sor to the power supply.
800
PIN 9
- EXC
+ EXC