Hach A1000 Basic User Manual page 15

Table 1 Digital input description
Input Function
Digital Input 1 (IN1) Starts an analysis (high-to-low state) when Digital Input
2 selects Auto TOC mode. The minimum period for a signal
pulse is 0.1 second.
Digital Input 2 (IN2) Selects the operating mode—Auto TOC mode (high state)
or Purge Only mode (low state).
Figure 12 Typical digital input wiring
1 Bias connector
Connect the digital outputs (optional)
N O T I C E
Do not use the digital outputs for process control functions such as pump on/off
switching or water system shutdown. The digital output connections do not
replace a PLC (programmable logic controller).
Connect a compatible device such as a remote alarm indicator or PLC to
the Outputs connector and Bias connector on the I/O connector block.
Refer to Figure 13.
The Outputs connector has two digital outputs. Refer to
digital outputs are 8.5 mA current sinks that share a common negative
terminal. The digital outputs supply power to solid state relay inputs and
have an input range of 5–30 VDC.
2 External power source
Table 2. Both
Table 2 Digital output description
Output Function
Digital Output 1 (OUT1) Transmits the TOC value as above or below the
selected alarm limit—below (high state) or above (low
state).
Digital Output 2 (OUT2) Transmits the status of the sample valve—open (high
state) or closed (low state).
Figure 13 Typical digital output wiring
1 Relay inputs 2 Solid state relay
Connect a printer (optional)
Connect a printer to the analyzer to get automatic and on-demand
printouts.
Connect a serial cable to the Printer connector on the I/O connector
block. Refer to Table 3 and Wiring overview
conductor serial cable is sufficient for most serial interfaces, depending
on the type of printer. AWG 24 is recommended.
The Printer connector is an RS232C series interface, 1200 baud and
8 data bits (1 stop bit, no parity), for a 40-column printer.
Table 3 Printer wiring
Terminal Description
TxD2 Data (white with blue stripe)
RxD2 Busy (blue with white stripe)
3 Relay outputs
on page 12. A three- or five-
Terminal Description
SG Ground
PG Not used
English 15