Flowserve AF-17 Electronic Positioner - Manual (Page 16)

3.6 Input Signal Connections
NOTE: The 120/240 VAC AF-17 positioner board signal input circuit is protected by a 1 /
16
amp fuse, F1. See Figure 1 and
Paragraph A of Part 1.1.
3.6.1 AF-17-1, AF-17-4, AF-17-10 (Milliamp Input Signal for AF-17)
For a milliampe signal input, the more positive or “High” signal lead should connect to terminal 11. The less positive or
“Common” lead should connect to terminal 10. Terminal 10 is (-), Terminal 11 is (+).
This positioner is available for use with the standard milliamp signals: 1 to 5, 4 to 20, and 10 to 50 milliamps. The
positioner board is factory calibrated for one of the three milliamp signal ranges, and field changes are not advised. A label
on the circuit board indicates the positioner’s signal range.
Paragraph 6.4.1 gives the nominal resistance load, which the positioner presents to the control circuit for the three
signal ranges.
Comparison of resistance measurements made at terminals 10 and 11 (on the yellow and blue wires from the circuit board)
against the resistances shown in paragraph 6.4.1 provides a quick way to determine the milliamp range for which a
particular board is calibrated.
NOTE: If the circuit board has an orange wire (See Figure 1) attached to it, the board is for a Resistive Input. See
Paragraph 3.6.2 and Figure 8.
3.6.2 AF-17-13, AF-17-1K (Resistive Input for AF-17)
NOTE: The Resistive Input Potentiometer is not the Feedback Potentiometer, but is an additional Potentiometer
provided and externally located by user.
For a resistance input signal, the usual connections will be similar to that shown in Figure 8 with a “Close” command being
generated where the potentiometer of Figure 8 is rotated to its full CCW position and an “Open” command when it is in the
full CW position.
If the command signal is derived from other than a rotary potentiometer, it is only necessary to keep in mind that a “Closed”
(full CW) valve is called for when the command potentiometer presents the least resistance between terminals 10 and 11
and the most resistance between terminals 11 and 12. A full “Open” (full CCW) valve would be the reverse condition; the
least resistance between terminals 11 and 12 and the most resistance between terminals 10 and 11.
If the “Command” potentiometer is reasonably linear, the actuator/valve will be approximately 50% open when the
resistances between terminals 10 to 11 and 11 to 12 are equal.
Resistive input circuit boards are made in two versions, one for high resistance command circuits – 1000 ohms nominal,
and one for low resistance command circuits – 135 ohms nominal.
Figure 8
16 AF-17 Electronic Positioner: Installation, Operation and Maintenance WCAIM2031
Flow Control Division
Worcester Controls