PLCs analog capability has improved, particularly
with the larger units. However, there are still many PLC product lines that
have Non-isolated analog inputs.
The customer had a PLC bringing in several analog signals from the field
(i.e., pump discharge, tank levels, etc.). There were several problems:
several transmitters were sourcing 4-20mAdc, the PLC was also powering the
loop, and the PLC had non-isolated inputs.
As you know, the BVS is a ready solution for this situation. The wiring
of the BVS is much simpler than the PLC wiring. If you study the attached
connection drawing long enough, you can figure out that the sourced power
is on 2, and the return is on 3. That's for loop 1, and this continues for
16 points.
In many PLCs, the BVS can keep the customer from having to use a more expensive
card, or even having to go to a higher priced PLC Series. We help them keep
it simple. |
