Table of Contents
Advertisement
04:
Z=X+F (P34)
1:
1
2: -24
3:
3
05:
Z=X*F (P37)
1:
3
2:
-.0698
3:
3
06:
Z=X+Y (P33)
1:
3
2:
2
3:
2
07:
IF (X<=>F) (P89)
1:
5
2:
1
3:
0
4:
30
08:
Z=X+F (P34)
1:
2
2:
47.23
3:
4
09:
Z=F (P30)
1:
1
2:
0
3:
5
10:
End (P95)
11:
Z=X-Y (P35)
1:
4
2:
2
3:
6
7.14 4 TO 20 MA SENSOR USING
CURS100 TERMINAL INPUT
MODULE
A dew point sensor has a 4 to 20 mA output
over the dew point temperature range of -40 to
+70 C. The dew point sensor output may be
measured by the CR510 using the CUS100
Terminal Input Module (TIM). The CUS100
uses a 100 ,
0.01 % resistor to convert the 4
to 20 mA range to 400 to 2000 mV. The
millivolt range was found using the relationship
V = IR, where V is voltage, I is current, and R is
resistance, e.g. the voltage at -40°C is given by
V = 4 mA
100
= 400 mV. The dew point
sensor is measured with Instruction 2 (Volt Diff).
The multiplier for dew point temperature is
found with the following relationship [70°C -
SECTION 7. MEASUREMENT PROGRAMMING EXAMPLES
X Loc [ Temp
]
F
Z Loc [ Temp_Comp ]
X Loc [ Temp_Comp ]
F
Z Loc [ Temp_Comp ]
X Loc [ Temp_Comp ]
Y Loc [ Pressure ]
Z Loc [ Pressure ]
X Loc [ Cmpile_Ck ]
=
F
Then Do
X Loc [ Pressure ]
F
Z Loc [ Offset
]
F
Exponent of 10
Z Loc [ Cmpile_Ck ]
X Loc [ Offset
]
Y Loc [ Pressure ]
Z Loc [ Distance ]
(-40°C)] / [2000 mV - 400 mV] = 0.06875°C/mV.
The offset is found by taking the linear
relationship °C = mV
Mult + Offset and solving
for the Offset. At -40°C the voltage is 400 mV,
thus the Offset = -40 - [400 mV
0.06875°C/mV] = -67.5°C.
CONNECTIONS
The dew point sensor is measured with a
differential voltage measurement on differential
analog input 1. The CURS100 TIM and dew
point sensor are wired to the CR510 terminal
strip panel as shown in Figure 7.14-1.
PROGRAM
01:
Volt (Diff) (P2)
1:
1
Reps
2: 25
2500 mV 60 Hz Rejection
Range
3:
1
DIFF Channel
4:
1
Loc [ Dew_Pnt_C ]
5:
.06875 Mult
6: -67.5
Offset
INPUT LOCATIONS
1 Dew_Pnt_C
7-17
Advertisement
Chapters
Table of Contents
