Introduction—ASC and N2 Bus Networking and Troubleshooting Guide 21
VOLTAGE
N2+ to REF
+2.45 to 2.98 VDC
N2+ to N2-
+0.36 to 0.92 VDC
N2- to REF
+2.06 to 2.54 VDC
GND
N2 Bus Terminal Block on
MM-CVT101 or Panel/
LTD
Companion
DMM
N2 -
N2 +
REF
For best reading, place probe on metal
plate inside terminal, not on screw.
Note:
Figure 10: Measuring RS-485 N2 Bus Converter Circuitry
3.
Power the ASC. For LCPs manufactured before January 1991, go on
to Step 4. For LCPs manufactured after January 1991, and all other
ASCs, continue with this step.
Before connecting the N2 Bus, check the voltage and polarity of the
N2 DC bias voltages on the ASCs. Do so by connecting the DMM
across N2+ and REF (Figure 11). Write down the reading. Repeat for
N2– and REF, then for N2+ and N2–. Compare the voltages you read
to the following values:
N2+ to REF = +2.45 to 2.98 VDC
N2– to REF = +2.06 to 2.54 VDC
N2+ to N2– = +0.36 to 0.92 VDC
If your readings are not (approximately) at these values and the ASC
does not communicate, replace the ASC.
If your readings are within these values, go on to Step 4.
Summary of Contents for METASYS ASC
Page 4: ...4 Introduction ASC and N2 Bus Networking and Troubleshooting Guide ...
Page 10: ...10 Introduction ASC and N2 Bus Networking and Troubleshooting Guide ...
Page 30: ...30 Introduction ASC and N2 Bus Networking and Troubleshooting Guide ...
Page 32: ...32 Introduction ASC and N2 Bus Networking and Troubleshooting Guide ...
Page 42: ...42 Introduction ASC and N2 Bus Networking and Troubleshooting Guide ...