31
Logix
®
520MD+ and 510+ Digital Positioners FCD LGENIM0105-15-AQ – 05/16
flowserve.com
7.4 V to I Card Connections
The V to I card is used if powering the positioner using a voltage
generator is desired. The card requires a voltage input and converts
the voltage to a current suitable for powering the positioner. The posi-
tioner can still communicate via a HART interface on the voltage lines.
NOTE:
When using the V to I card, digital position control is
recommended. Controlling position by changing the voltage may
result in lack of position linearity and accuracy.
Wire the V to I card according to Figure 32: V to I Card Circuit. Con-
nect the voltage input to the V to I card terminal. Connect the red wire
from the V to I card to the positive terminal on the main board 4-20
mA input connector. Connect the black wire from the V to I card to
the negative terminal on the main board 4-20 mA input connector.
Current to the positioner can be approximated by the formula in
Equation 4.
Equation 4
I =
(Supply Voltage-Terminal Voltage)
696
Example
Supply Voltage = 24 V
Terminal Voltage = 10 V
I =
(24-10)
= 20 m
A
696
Figure 31: V to I Card
Figure 33: V to I Card installed
Figure 32: V to I Card Circuit