User's Manual

Operation
3A1149D 19
Primary DGM Analog Inputs
See Analog Inputs table in the Primary DGM Pin
Assignments section beginning on page 10 for pin
numbers associated with each bit description.
The DGM provides 4 analog inputs and 4 analog out-
puts. Each analog I/O point has a voltage range of
0-10 VDC. Analog Inputs 2, 3, and 4 are not used.
It is the responsibility of the PLC programmer to verify
the HFR system and PLC have matching values for
pump sizes, material specific gravities, maximum work-
ing pressure, and units of measure for pressure. These
are verified using the Setup screens in the ADM.
Analog Input 1: Set Combined Flow Rate or
B (Blue) Dispensing Pressure
To calculate the input voltage for the desired flow or
pressure, use the following formulas.
Volumetric Flow:
V = ( 10 x F
v
) / ( A
p
+ B
p
)
Weight Flow:
V = ( 10 x F
w
) / ( A
p
x A
sg
+ B
p
x B
sg
)
Pressure:
V = ( 10 x P
d
) / ( P
mwp
)
where,
V = Voltage
A
p
= A (Red) pump size in cc
B
p
= B (Blue) pump size in cc
A
sg
= A (Red) material specific gravity
B
sg
= B (Blue) material specific gravity
F
v
= Desired volumetric flow rate in cc per second
F
w
= Desired flow rate in grams per second
P
d
= Desired pressure
P
mwp
= Maximum working pressure
For example, if the A (Red) pump is 120 cc, the B (Blue)
pump is 160 cc, and the desired flow rate is 180 cc per
second then:
V = (10 x 180) / (120 + 160)
= 6.43 volts
If the A (Red) pump is 120 cc, the A (Red) specific grav-
ity is 1.09, the B (Blue) pump is 160 cc, the B (Blue)
specific gravity is 1.21, and the desired flow rate is 200
grams per second then:
V = (10 x 200) / (120 x 1.09 + 160 x 1.21)
= 6.17 volts
If the desired pressure is 1500 psi and the maximum
working pressure is 2000 psi then:
P
d
= 1250
P
mwp
= 2000
V = (10 x 1500) / (2000 )
= 7.5 volts
To set the flow or pressure:
1. Calculate the voltage to use.
2. Set the Analog Input 1 to the calculated voltage and
hold.
3. After 185 mS, pull the corresponding Digital
Input 16 bit for 185 mS then release Digital Input 16.
4. Check Digital Output 4 to verify the setpoint request
was not rejected.