West Control Solutions N8080 (for 1xxx) - Manual (Page 21)

1.3.5 Digital Input Option
Terminals 16 and 17, when this option is fitted, may be used for external selection
of the Security facility) which allows/prevents entry into Program Mode from the
front panel. These terminals may be connected to (a) the voltage-free contacts of
a switch or relay, or (b) a TTL-compatible voltage. With the Security option
configured (see Subsection 3.4), security selection is as follows:
Voltage-free Operation: Contacts open - Entry into Program Mode
prohibited
Contacts closed - Entry into Program Mode
permitted
TTL-compatible Operation: >2.0V - Entry into Program Mode
prohibited
<0.8V - Entry into Program Mode
permitted.
NOTE: This option and the Serial Communications option are
mutually exclusive.
1.3.6 Relay Outputs
Relay 1 is a standard feature; it is tied to Alarm 1. Relay 2 is an option; when fitted,
it is tied to Alarm 2. The contacts are rated at 2A resistive @ 120/240V AC.
1.3.7 Linear Output
This option provides a 10-bit linear output signal representing the process
variable. The range of this output is selectable in Configuration Mode (see
Subsection 3.4).
1.3.8 Serial Communications Option
The cable used should be suitable for data transfer at the selected rate (1200,
2400, 4800 or 9600 Baud) over the required distance. Transmitters/receivers
conform to the recommendations in the EIA Standard RS485.
The “A” terminal on the Indicator (Terminal 17) should be connected to the “A”
terminal on the master device; the “B” terminal on the Indicator (Terminal 16)
should be connected to the “B” terminal on the master device; the “Common”
terminal on the Indicator (Terminal 18) should be connected to the “Common”
terminal on the master device.
PM090-1 Volume II 1-5
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