Detcon PI-600 - Manual (Page 17)

Note: If a voltage signal output is desired in place of the 4-20mA output, a 1/4 watt resistor must be installed in posi-
tion R1 of the terminal board. A 250
Ω resistor will provide a 1-5V output (– to mA). A 100Ω resistor will provide a
.4-2V output, etc. This linear signal corresponds to 0-100% of scale (see f igure 3).
e) Program the alarms via the gold plated jumper tab positions located on the CPU board (see f igure 3A). Alarm 1
and Alarm 2 have three jumper programmable functions: latching/non-latching relays, normally energized/normally
de-energized relays, and ascending/descending alarm set points. The fault alarm has two jumper programmable func-
tions: latching/non-latching relay, and normally energized/normally de-energized relay. The default settings of the
alarms (jumpers removed) are normally de-energized relays, non-latching relays, and alarm points that activate dur-
ing descending gas conditions.
If a jumper tab is installed in the latch position, that alarm relay will be in the latching mode. The latching mode will
latch the alarm after alarm conditions have cleared until the alarm reset function is activated. The non-latching mode
(jumper removed) will allow alarms to de-activate automatically once alarm conditions have cleared.
If a jumper tab is installed in the energize position, that alarm relay will be in the energized mode. The energized mode
will energize or activate the alarm relay when there is no alarm condition and de-energize or de-activate the alarm
relay when there is an alarm condition. The de-energized mode (jumper removed) will energize or activate the alarm
relay during an alarm condition and de-energize or de-activate the alarm relay when there is no alarm condition.
If a jumper tab is installed in the ascending position, that alarm relay will be in the ascending mode. The ascending
mode will cause an alarm to f ire when the gas concentration detected is greater than or equal to the alarm set point.
The descending mode (jumper removed) will cause an alarm to f ire when the gas concentration detected is lesser
than or equal to the alarm set point. Except in special applications, toxic gas monitoring will require alarms to f ire
in “ASCENDING” gas conditions.
Any unused jumper tabs should be stored on the connector board on the terminal strip labeled “Unused Jumpers”
(see f igure 3).
f) If applicable, set the RS-485 ID number via the two rotary dip switches located on the preamp board (see f igure
3B). There are 256 different ID numbers available which are based on the hexidecimal numbering system. If RS-485
communications are used, each sensor must have its own unique ID number. Use a jewelers screwdriver to set the
rotary dip switches according to the table listed on the following page. If RS-485 communications are not used,
leave the dip switches in the default position which is zero/zero (0)-(0).
PI-600 Toxic Gas Sensors PG.17
FAULT
ALARM 1
Latch
Energize
Latch
Ascending
Energize
A
LA
R
M
2
La
tc
h
A
sc
en
di
ng
E
ne
rg
iz
e
CPU Board - Top View
Alarm Programming Jumpers
Control Circuit - Side View
CPU Board
Figure 3A