Teledyne 4220 - Manual (Page 117)

4220 Flow Meter
Section 5 Options and Accessories
5-9
and the other for low. The availability of form C contacts (both
NO [normally open] and NC [normally closed] contacts) means
you can switch loads either on or off. Relay contacts are rated 3
Amperes at 24 volts AC or DC. The alarm box operates on 12
VDC supplied from the flow meter. Current consumption in
standby condition is approximately 10 mA. In alarm, current
increases to 190 mA. You can connect as many as four alarm
boxes to a flow meter, if the flow meter is powered from the AC
line.
Note
Do not use the alarm box if your flow meter has a modem or
uses Flowlink software (through either a modem or laptop
computer).
Use the alarm box with caution in battery-powered installa-
tions, as it will significantly increase power consumption.
In standby condition, an alarm box consumes about one
ampere-hour of battery capacity in four days (or reduces capacity
approximately 25%). In alarm condition, one alarm box will com-
pletely discharge a fresh (4 Ah) battery in 21 hours. Teledyne
Isco recommends using only one alarm box in a battery - powered
installation, and you can expect to change the battery more
often.
5.6.1 Installation The High-Low Alarm Relay Box is enclosed in a high-strength
plastic box and is easily installed. Mount the unit with cor-
rosion-resistant hardware through the 2 holes in the stainless
steel mounting plate attached to the case. Two threaded holes in
the case allow the use of either
1
/ 2 " conduit fittings or com-
pression bushings. While the alarm box is suitable for use in
damp locations, do not install it where there is any possibility of
submersion. Where temperatures are expected to fall below
freezing, Teledyne Isco recommends installation of the alarm box
indoors or in a heated location, as the manufacturer of the micro-
processor does not specify its operation below 32° F (0° C).
DANGER
Hazard of electric shock! Use the relay contacts
for low voltage (24 V) pilot duty only. Do not wire
120 VAC or higher voltages to the relay contacts.
5.6.2 Wiring to a 4200 Series
Flow Meter
Connecting the High-Low Alarm Relay Box to a 4200 Series Flow
Meter requires a cable and an M/S connector. A special cable, 25
feet long, is available from Teledyne Isco. On one end of the cable
is a 4-pin, male M/S connector. Plug this connector into the
Remote Printer/Rain Gauge connector on the flow meter. The