Alarm Relays; Alarm Relay Connections - Hach Sigma 950 Instrument Manual

Communications Setup

8.4 Alarm Relays

8.4.1 Alarm Relay Connections

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6. Select Unit of measurement (ppm, ppb, afd, cfs, cfm, cfd, cms, cmm, cmh, cmd, gps,
gpm, gph, lps, lpm, lph, or mgd).
7. Enter Low Point.
8. Apply minimum current output (4 mA) from other instrument.
9. Enter High Point.
10. Apply maximum current output (20 mA) from the other instrument.
11. Select another channel to configure, or press
function key to return to the Main Menu.
MAIN MENU
Example: A dissolved oxygen meter has an analog output signal that will connect to the
950 Flow Meter analog input channel 4. The DO meter puts out an analog signal which
ranges from +1 V dc to +3 V dc, which is equivalent to 0 to 500 ppm. The DO meter is
connected to Channel 1 and log readings from the DO meter occur once per minute.
To configure data logging for this example, follow the steps below.
1. Select from the Advanced Options menu.
DATA LOG
2. Highlight
SELECT INPUTS
3. Highlight the analog channel to log (Channel 4) using the
then press .
SELECT
4. Press
CHANGE CHOICE
5. Enter a 1-minute logging interval using the numeric keypad, then
press .
ACCEPT
6. Press
CHANGE CHOICE
Press .
ACCEPT
7. Apply a voltage to the desired analog input which corresponds to 0 ppm (or +1 V dc).
Enter 0 ppm using the numeric keypad and press
8. Apply a voltage to the same analog input that corresponds to 500 ppm or +3 V dc.
Enter 500 ppm using the numeric keypad and then press
analog channel setup.
Note: One cable is required for each set of two installed relays.
Up to four optional alarm relay outputs are available as factory installed options. Two
relays can be added at a time and each set of two relays share a single interface
connector.
Pin
A
B
C
D
E
F
using the and
UP DOWN
to select "Logged," then press
to cycle through the units of measure until ppm is displayed.
Table 27 Relay 1 & 2 Connector Pin Assignments
Signal Description
relay #1 N.O. (normally open)
relay #1 common
relay #1 N.C. (normally closed)
relay #2 N.O. (normally open)
relay #2 common
relay #2 N.C. (normally closed)
to back up one step. Press the
RETURN
soft keys and then press
and
UP DOWN
.
ACCEPT
.
ACCEPT
to complete the
ACCEPT
Wire Color
green
black
white
green
black
white
.
SELECT
soft keys,