You are looking at the RS-485-side of an RS-232/RS-485
converter and the power supply voltage for the converter is
+5V. Under idle conditions (no transmission), and assuming
you have enabled the RS-485 output: what would you expect
at:
(a) Output A measured against output B
(b) Output A measured against ground
(c) Output B measured against ground
Answer / carl_ellis
You are looking at the RS-485-side of an RS-232/RS-485
converter and the power supply voltage for the converter is
+5V. Under idle conditions (no transmission), and assuming
you have enabled the RS-485 output: what would you expect
at: (a) Output A measured against output B (b) Output A
measured against ground (c) Output B measured against ground
With a supply voltage of 5V, the sink driver is usually able
to pull the voltage on each conductor fairly close to signal
ground (0.5V), but the source driver usually has a voltage
drop of approximately 1-1.5V. The voltage swing on each
conductor is therefore typical 3-3.5V, but it may be as low
as approximately 2V.
Answer a)
Hence, output A (-) measured with respect to output B (+)
would read approx -3V to -3.5V ( a negative voltage) in the
idle state. (The logic is inverted: a negative voltage is a
mark or logic 1)
Answers b and c)
Output A (-) measured with respect to ground: ~3.5V to 4V
Output B (+) measured with respect to ground: ~0.5V to 1V
This is a 3V differential, with 2.5V Vcm common mode, where
common mode is the mean of the differential plus the Vcm
common mode above the reference ground.
Carl Ellis
Measure First
Is This Answer Correct ? | 3 Yes | 1 No |
The DCS stand for________________________. it is composed of the following major components: a:______________ b:______________ c:______________ d:______________
In dcs panel we are using diff type of modules ?what is module ? what is the use of modules ?diff type of module?
procedure to commission a drum level transmitter
How do bending tubing provide better measurement than using tubing fittings such as elbows?
What is difference of fanuc alpha series 16i and 18i controller.also what is differnce betn TC and MC controller
what is the differnce between PLC & DCS
plz send me placement paper of ongc
What is paid how it works
pressure gauge measure static pressure or dynamic pressure?
What is the Difference between E/P Positioner and I/P positioner in a control valve? In which applications the respective positioners are used in?
detail of mass flow meter pricipal
which types of oxygen analyzer describe with drawing ?