Electrical Connections - Teledyne HFM-301 Instruction Manual

301/303/305/306/307 Flowmeters and Controllers Instruction Manual

Electrical Connections

If a power supply from Hastings Instruments is used, installation consists of connecting the 300 series cable
from the "D" connector on the rear of the power supply to the "D" connector on the top of the flow
meter/controller. The "H" pin-out requires cable AF-8-AM (grey molded back-shell). The "U" pin-out requires
cable # 65-791 (black molded back-shell).
If a different power supply is used, follow the instructions below when connecting the flow instrument and
refer to either table 2.1 or 2.2 for the applicable pin-out. Also see section 1.3 for the 4-20 mA connections.
The power supply used must be bipolar and capable of providing the appropriate current draws mentioned in
section 2.2. These voltages must be referenced to a common ground. One of the "common" pins must be
connected to the common terminal of the power supply. Case ground should be connected to the AC ground
locally. The cable shield (if available) should be connected to AC ground at the either the power supply end,
or the instrument end of the cable, not at both. Pin 6 is the output signal from the flow meter. The standard
output will be 0 to 5 VDC, where 5 VDC is 100% of the rated or full-scale flow.
The command (set point) input should be a 0-5 VDC signal (or 4-20mA if configured as such) and must be free of
spikes or other electrical noise, as these would generate false flow commands that the controller would
attempt to follow. The command signal should be referenced to signal common.
A valve override command is available to the flow controller. Connect the center pin of a single pole, three-
position switch (center off) to the override pin. Connect +15 VDC to one end of the three-position switch, and
-15 VDC to the other end. The valve will be forced full open when +15 VDC is supplied to the override pin, and
full closed when -15 VDC is applied. When there is no connection to the pin (the three-position switch is
centered) the valve will be in auto control and will obey the 0-5 VDC commands supplied to command (set-
point) input.
WARNING: Care must be taken to avoid any high voltages that may be present when dealing
with power supplies. Power supplies used with 300 Series instruments should be power limited
to no more than 150 VA max. The available current for each 300 Series instrument connected
to a power supply should not exceed 1.6 A.
WARNING: Care must be taken to avoid any high voltages that may be present when dealing
with power supplies.
EAR99 Technology Subject to Restrictions Contained on the Cover Page Page 13 of 32