Hach-Lange WPC-22 - Manual (Page 9)

Connect the analog outputs (optional)
Two 4–20 mA analog outputs (AO1 and AO2) are available at the
J3 connector. The analog output signal is proportional to the counts/mL
of the channel. The counts/mL for Channel 1 is represented on AO1.
The counts/mL for Channel 2 is represented on AO2.
Connect a current receiving device to each analog output with
24–28 AWG wire. Refer to
Table 1 .
If the current receiving device(s) has a load resistor of 500 ohms or
more, supply external voltage (40 VDC maximum) to Vext– and Vext+ of
the J1 connector to supply sufficient voltage to the current receiving
device.
Table 1 Analog output connections (4–20 mA)
Pin Description
AO2– Neutral
AO2+ Positive
AO1– Neutral
AO1+ Positive
Connect the analog input (optional)
Two analog inputs (AI1 and AI2) are available on the J3 connector.
Connect auxiliary instruments (i.e., flow meters, turbidity meters,
pressure transducers, pH meter) to the analog inputs to show the
voltage supplied by the auxiliary instruments on the instrument display
(0–10 VDC). Refer to
Identify the analog input values on page 15.
Connect an auxiliary instrument to each analog input with 22–24 AWG
wire. Use 19 AWG wire instead if the wire is 7.62 m (25 ft) long or more.
Refer to
Table 2 .
Table 2 Analog input connections (0–10 VDC)
Pin Description
AI2– Neutral
AI2+ Positive
Table 2 Analog input connections (0–10 VDC) (continued)
Pin Description
AI1– Neutral
AI1+ Positive
Connect the digital input (optional)
One digital input is available on the J4 connector. Connect a flow
monitoring device to the digital input (CTS pin) to trigger a Flow alarm
when the voltage on the digital input is high or low, depending on the
Flow Alarm State setting. Refer to
Configure the particle counter
on page 13 to configure the Flow Alarm State setting and enable the
Flow alarm.
Connect the flow monitoring device to the CTS pin with 24–28 AWG
wire.
Note: The digital input is not available when the RS232 connection is used to
connect a printer or a computer.
Connect the digital outputs (optional)
Two digital outputs (ALM and CAL) are available on the J1 connector.
Refer to
Table 3 . Connect a compatible device such as a remote alarm
indicator or buzzer to the applicable digital output with 24–48 AWG wire.
The ALM pin and CAL pin are open collector outputs that supply a
ground connection when energized. Obey the digital output ratings in
Specifications on page 3.
Table 3 Digital output descriptions
Digital output Description
ALM pin Energizes when a Flow alarm or Count alarm is active. Refer to
Configure the particle counter on page 13 to configure the
Flow alarm and Count alarm.
CAL pin Energizes when a high or low calibration error is active.
English 9