Detcon 840 - Manual (Page 14)

840 Operators Manual
Model 840 Operator Manual Rev. 1.9 Page 10 of 29
6.
System Configuration
6.1 Analog/Serial input selection
On the Controller PCB, switch SW1 position 1 is used to select between Analog or Serial sensor inputs for
the 840 Controller. Switch SW1-1 must be placed in the “ON” position for the unit to accept Serial RS-485
Modbus™ sensors, and SW1-1 must be placed in the “OFF” position if the sensors are 4-20mA type
sensors (Figure 7). For Serial Inputs SW1-2 should be “ON” for use with Mod 10 Control Boards, and
“OFF” for use with Detcon 600 or 700 Series Sensors. SW1-2 has no effect when SW1-1 is set for Analog
(“OFF” Position).
NOTE: Incorrect placement switch SW1-1 when using Serial Sensors will cause the unit to display
“FAULT” on all channels, and the “FAULT” LED will be lit. Incorrect placement of switch SW1-1 when
using Analog Sensors will cause the unit to display “NO-COMM” on all channels, and the “FAULT” LED
will be lit. When using Serial Sensors or Mod 10 Controller inputs ensure that SW1-2 is in the correct
position for the type of sensor or controller being polled or the unit will display incorrect readings.
RS-485 Input for
Gas Sensors
1 2 3 4 ON
OFF
Switch SW1
Pos 1 - Analog or Serial Mode
Pos 2 - 600/700 Series Sensors or
Mod 10 Controllers
Pos 4 - Password Protected
Part of Control Board
Figure 7 Switch SW1
6.2 Password Protection
Password protection is accomplished via a switch selection on the backside of the Controller PCB (Figure 7
SW1). With Switch SW1 position 4 in the OFF position, the Controller will be in Password Protected
mode. In this mode, there is no access to the Menus. The only functionality provided for is the Main
Display and the use of the Reset and Acknowledge functions. With SW1-4 in the ON position, Password
Protection is turned off and there is complete access to the Menus.
6.3 Navigating the Menus
The menu text is displayed on the backlit LCD and is interfaced via the four function keys located below it.
These keys are labeled from left to right: PROG, UP, DOWN, ENTER. The ENTER key is a multiple-use
key that also controls the Reset and Acknowledge relay functions. With reference to the Menu Flow Chart
(See Figure 9) and the correct function key sequencing, it is easy to learn how to navigate the menus, make
changes, and access the logged data.