Fluke 225C User Manual - Page 84

RS-485 Bus & MOD Bus IEA-485/RS-485, RS-485 Bus Measurement Connections

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Fluke 19xC-2x5C Users Manual RS-485 Bus & MOD Bus IEA-485/RS-485 Default probe setting 10:1. Use the Fluke 10:1 probes. 1 Connect the red probe to the test tool input A and the grey probe to input B. 2 Connect the ground lead of the input A probe to the RS-485 bus RxD/TxD N (-) 3 Connect the ground lead of the input B probe to the RS-485 bus cable shield. 4 Connect the probe tip of both probes to the RS-485 bus RxD/TxD P (+) DATA + DATA DATA GND Table 6. RS-485 Bus Tested Signal Properties Signal V-Offset V-Level Data Rise Fall Jitter Signal Dist. Overshoot Description High level voltage Peak-peak voltage Bit width Rise time as % of bit width Fall time as % of bit width Jitter distortion Signal distortion (Manchester decoding, default setting) Overshoot (NRZ decoding, can be selected via limit setup) Note Continuous data traffic is not ensured . See Data Traffic on page 70 Figure 40. RS-485 Bus Measurement Connections 74

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Fluke 19xC-2x5C
Users Manual
74
RS-485 Bus & MOD Bus IEA-485/RS-485
Default probe setting 10:1. Use the Fluke 10:1 probes.
1
Connect the red probe to the test tool input A
and the grey probe to input B.
2
Connect the ground lead of the input A probe to
the RS-485 bus RxD/TxD N (-)
3
Connect the ground lead of the input B probe to
the RS-485 bus cable shield.
4
Connect the probe tip of both probes to the
RS-485 bus RxD/TxD P (+)
DATA +
DATA -
DATA GND
Figure 40. RS-485 Bus Measurement Connections
Table 6. RS-485 Bus Tested Signal Properties
Signal
Description
V-Offset
High level voltage
V-Level
Peak-peak voltage
Data
Bit width
Rise
Rise time as % of bit width
Fall
Fall time as % of bit width
Jitter
Jitter distortion
Signal Dist.
Overshoot
Signal distortion (Manchester
decoding, default setting)
Overshoot (NRZ decoding, can be
selected via limit setup)
Note
Continuous data traffic is not ensured . See Data
Traffic on page 70