GDS-68XP Operation & Maintenance Manual, Revision 3.4
Page 29
CALIBRATION PROCEDURE (CAL PORT SAMPLE)
Calibration using the built-in calibration port is the fastest and most
convenient method. When the GASMAX enters CAL MODE, the purge
air pump automatically turns on to provide zero air flow from
ambient air; sample air flow is provided by the fixed flow regulator
connected to the calibration gas cylinder.
CALIBRATION PROCEDURE – CALIBRATION PORT
OBTAIN THE FOLLOWING ITEMS:
1) CYLINDER OF CALIBRATION GAS WITH FIXED FLOW REGULATOR AND LENGTH OF FLEXIBLE TUBING
2) CYLINDER OF ‘ZERO AIR’ IF NECESSARY
IF NOT PREVIOUSLY DONE:
1) VERIFY THAT THE CHANNEL 1
CAL SPAN VALUE
MATCHES THE CALIBRATION GAS TO BE USED
2) VERIFY THAT THE CALIBRATION GAS IS NOT EXPIRED
ENTER CAL MODE:
WAIT UNTIL THE SEQUENCER IS IN PURGE/HOLD MODE
AS
INDICATED BY “L2” (GREEN) FLASH
PRESS THE “CAL” KEY FOLLOWED BY THE “EDIT” KEY
ATTEMPTING TO CALIBRATE THE GASMAX
DURING A SAMPLE SEQUENCE WILL RESULT IN
A CALIBRATION ERROR
THE “APPLY ZERO GAS” SCREEN WILL APPEAR; L2 WILL CHANGE TO SINGLE FLASH
PURGE AIR PUMP WILL TURN ON AND AMBIENT (“ZERO”) AIR WILL FLOW INTO THE SENSOR FLOW CELL
SET THE ZERO VALUE:
ALLOW THE READING TO STABILIZE AND
PRESS THE “EDIT” KEY TO
ACCEPT
THE CURRENT READING AS ‘ZERO’
IF THERE IS A POSSIBILITY THAT TARGET GAS
MAY BE PRESENT IN AMBIENT AIR, USE A
CYLINDER OF ZERO AIR IN PLACE OF PURGE AIR
IF ZERO READING IS WITHIN LIMITS, THE
ZERO CAL SUCCESS
SCREEN WILL MOMENTARILY APPEAR
THE “APPLY SPAN GAS” SCREEN WILL APPEAR
SET THE SPAN VALUE:
CONNECT THE SPAN GAS AS SHOWN ABOVE, SET THE RUN/CAL
VALVE TO “CAL” AND TURN ON THE REGULATOR. VERIFY FLOW ON
THE FLOW METER. ALLOW THE READING TO STABILIZE AND
PRESS
THE “EDIT” KEY TO ACCEPT
THE CURRENT READING AS ‘SPAN’
ALLOW THE GAS TO FLOW FOR ABOUT AS
LONG AS IT DOES DURING A NORMAL
SEQUENCE, USUALLY BETWEEN THREE AND
FOUR MINUTES.
IF SPAN READING IS WITHIN LIMITS, THE
SPAN CAL SUCCESS
SCREEN WILL MOMENTARILY APPEAR
THE GASMAX DUAL SCREEN WILL REAPPEAR SHOWING CHANNEL 1 IN PURPLE (CAL DELAY)
COMPLETE CALIBRATION:
DISCONNECT THE SPAN GAS CYLINDER AND SET THE RUN/CAL
VALVE BACK TO “RUN”
ONCE CAL PURGE DELAY IS COMPLETE, THE
SEQUENCER WILL RETURN TO THE
PURGE/HOLD MODE
Figure 7-1: Calibration Procedure (Cal Port)