Instruction manual

AM16/32 Relay Analog Multiplexer

'CR5000 Example Program to measure 16 100 ohm Platinum Resistance Thermometers ‘connected to an

AM16/32 multiplexer used in the 4x16 configuration. The program also ‘measures 6 copper constantan

'thermocouples.

'The Thermocouples are connected to differential channels 1-6.

'Declare Variables:

Public TRef, TCTemp(6), PRTResist(16), PRTTemp(16)

Dim I 'Counter for setting Array element to correct value for mux measurement

'Declare Output Table for 15 minute averages:

DataTable (Avg15Min,1,-1)

DataInterval (0,5,Min,10)

Average (1,TRef,IEEE4,0)

Average (6,TCTemp(),IEEE4,0)

Average (16,PRTTemp(),IEEE4,0)

EndTable

BeginProg

Scan (60,Sec,3,0)

PanelTemp (TRef,250)

TCDiff (TCTemp(),6,mV20C ,1,TypeT,TRef,True ,0,250,1.0,0)

Portset (1 ,1) 'Set C1 high to Enable Multiplexer

I=0

SubScan(0,sec,16)

'Pulse C2 (Set High, Delay, Set Low) to clock multiplexer

Portset (2,1 )

Delay (0,20,mSec)

Portset (2,0)

I=I+1

'The Resistance measurement measures the PRT resistance:

Resistance (PRTResist(I),1,mV50,7,Ix1,1,500,True ,True ,0,250,0.01,0)

'With a multiplier of 0.01 (1/100) the value returned is R/Ro (Resist/Resist @ 0 deg)

'the required input for the PRT temperature calculation instruction.

NextSubScan

Portset (1 ,0) 'Set C1 Low to disable Multiplexer

‘Calculate the Temperature from R/Ro:

PRT (PRTTemp(1),16,PRTResist(1),1.0,0)

CallTable Avg15Min‘Call the DataTable

NextScan

EndProg

5.3.2 CR1000 Programming

The following CR1000 program uses the AM16/32 to measure 48

CS616 probes connected in the 4x16 configuration. The program also

measures datalogger battery voltage and temperature.