For assistance, call RITRON at 800-872-1872, or go to
www.ritron.com
14
NOTE: With Input #2 in On/OFF mode, Quick Talk
TM
functions normally with the external switch closed. When the
switch is open, Quick Talk
TM
is disabled and will not transmit messages. When the On/Off switch has been open
(Quick Talk
TM
disabled), and it is then closed, Quick Talk
TM
transmits the prerecorded message describing the current
condition of Input #1.
M
ONITOR
4-20
M
A
S
ENSOR
C
URRENT
L
OOP WITH
Q
UICK
T
ALK
TM
A
NALOG
I
NPUT
..............................................
Quick Talk
TM
can act as a current sink when a resistor is connected between an Input’s positive and negative
connection. The resistance value is selected to scale the current to the permitted 0 - 5 Volt range for the Input to
Quick Talk
TM
. The following formula is used to calculate the Analog Threshold Setpoints necessary for your
application.
Analog Threshold Setpoint =
4-20 ma current (Amps) times the resistor value (Ohms)
NOTE: A resistor value of 250
Ω
provides the maximum resolution, and is the recommended value. Using a lower
resistance value with the 4-20 mA current loop produces less than 5 V at the Input and the measurement resolution is
reduced. Using a higher resistance value at 20 mA can produce a voltage greater than 5V at the Input, which will not
be recognized.
To configure an Input for 4-20 mA current loop:
1. Connect a resistor between the two wires on the Quick Talk
TM
color-coded cable that are associated with the
desired Input (see Table 6)
2. Connect the output of the 4-20 mA current loop device to the positive (+) wire of the Input connection.
3. Program the desired Input for Analog Input operation and for the calculated Analog Setpoints.
4. Record an Input OPEN and Input CLOSED message for the associated Input.
