SERIAL Digital I/O Series User Manual Eagle Technology - Data Acquisition
Temperature Input
The SRL 73T-8/16/32 has a basic 8 differential channel configuration (See table 3-7),
accessible via a DB25M connector. The channels on one of these DB25M connectors will be
referred to as a channels set. Each SRL 73 is supplied with a set of µDAQ TEMP T/C
ADAPTERS.
Temperature measurements can be done with as little as four lines of code.
Reading CJC Channel
Each channels set has a CJC channel. The CJC channels is use in software when calculating
the temperature for
C
old Junction Compensation, hence CJC. Each of the µDAQ TEMP T/C
ADAPTERS has a circuit that will supply a voltage of 10mVolt per 1 degree C. Reading the
CJC channel is as easy as reading an analog channel. Each of the CJC channel is allocated
a channel number witch are always the last channels of any device.
E.g. if your device has two CJC channels and 34 analog channels, channel 0-31 will be
analog inputs and channels 32 and 33 will be the CJC channels.
The table shows the normal CJC assignment for the SRL 73.
Device CJC Channels
SRL 73T-8
CJC Value Assigned
0 8
SRL 73T-16
CJC Value Assigned
0 16
1 17
SRL 73T-32
CJC Value Assigned
0 32
1 33
2 34
3 35
Table 4-9 CJC Channels Assigned
The value that is assigned to a CJC channel can be queried with software as well.
API-CALL
Long EDRE_Query (ulng Sn, ulng Code, long Param)
Serial number, Query code ADAMBCHAN or 141 and the param that represent the CJC
channel 0-3. A return code will indicate the channel assigned or if any errors occurred.
ACTIVEX CALL
Long EDREUtlX.Query (ulng Channel, long uVoltage)
Query code ADAMBCHAN or 141 and the param that represent the CJC channel 0-3. A
return code will indicate the channel assigned or if any errors occurred.
Reading the CJC channel
API-CALL
Long EDRE_ADSingle (ulng Sn, ulng Channel, ulng Gain, ulng Range, plong uVoltage)
Parameter Type Description
Sn Unsigned long Device serial number
Channel Unsigned long Assigned Channel
Gain Unsigned long NULL
Range Unsigned long NULL
uVoltage Pointer to long Returned micro voltage
Return long Error code
ACTIVEX CALL
Long EDREADX.SingleRead (long Channel)
Only the assigned channel value is needed. A return code will indicate the voltage in
microvolt.
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