RKI Instruments RI-215A - Manual (Page 8)

8 • Internal Description RI-215A Operator’s Manual
On the bottom of the front housing is a series of slots and a calibration port. The slots
allow the target gas sample to enter the IR gas sensor in the RI-215A. The calibration port
is covered with a rubber cap. The calibration port accepts
1 /
4
-inch ID (inside diameter)
flexible tubing. A series of switches are accessible to the right of the calibration port, as
shown in Figure 1 on page 7. These switches include:
• Mode (M)
• Up/Alarm ( ∆ )
• Down ( ∇ )
• Set/Calibration (S)
The base plate has a wire entry slot for the cable assembly. The cable assembly connects
directly to the printed circuit board inside the case through the cable entry slot. The cable
assembly is used to connect to an external power source. You also use it to make
connections to an external alarm and to a monitoring or recording device. The base plate
has two mounting holes for convenient mounting on vertical surfaces at the monitoring
site.
Cable Assembly
The cable assembly connects to a six-pin receptacle on the printed circuit board through a
slot on the rear of the case. It allows you to make external wiring connections to the RI-
215A.
Internal Description
Printed Circuit Board
On the printed circuit board is located the IR gas sensor, LCD, and fuse. Connected to the
printed circuit board is the cable assembly.
The printed circuit board converts the output of the IR gas sensor to a 4-to-20 mA signal
(that is proportional to the detection range of the RI-215A). The printed circuit board also
displays a digital reading on the LCD.
The printed circuit board has four switches: Mode (M), Up/Alarm ( ∆ ), Down ( ∇ ), and
Set/Calibration (S). These switches are located at the bottom of the printed circuit board
beneath the gas sensor. Table 2 lists each switch and its function.
Table 2: Model RI-215A Program Switches
Switch Function
Mode (M) Enters Maintenance Mode
Up/Alarm ( ∆ ) • Increases the setting on the LCD
• Displays the alarm point
Down ( ∇ ) • Decreases the setting on the LCD
Set/Calibration (S) • Prepares a setting to be changed
• Enters a new setting