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3.3 CJC Output
The OME-DB-889D provides Cold-Junction Compensation (CJC) for the
thermocouple applications. If the CJC is required, place the JP17 in the position of the
channel to be used as a CJC reference. If the CJC is not required, Place the JP17 in
the position “X”.
CJC has output on connector CN7. Using a voltage meter measures CN7 which exists
a voltage related to the OME-DB-889D board temperature. The CJC voltage transfers
to temperature with formula:
T(°C) = V*1000/24.4
-
+
CN7
CJC output
Voltage meter
A.GND
V: Voltage of CN7
T: Temperature of OME-DB-889D
Example: (Turbo C)
Multi-Function Card: OME-A-822PGL
The OME-DB-889D JP17 placed on “7”.
/*====================Example Program ===================*/
#include <stdio.h>
#include “A822.h>
main(void)
{int ad_channel , gain , trigger_mode, poll_data ;
float temp;
A822_Initialize(0,0x220, -1, -1);
/* Initials OME-A-822PGL Ref. OME-A-822PGH/L Software
Manual */
ad_channel=7;
gain=0;
trigger_mode=1;
for(;;)
{
A822_AD_SetChGainMode(ad_channel , gain , trigger_mode );
/* SettingOME-A-822 A/D channel =7 , Gain=1 , Trigger mode = Software
trigger */
poll_data=A822_AD_PollingVar();
temp=(float)(((poll_data-2048)*5/2048)*1000/24.4);
prinf(“ Temperature = %4.1f °C \n”, temp);
}
}
OME-DB-889D User’s Manual
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