Operation Using a Programmable Logic Controller (PLC)
Digital
Digital
Digital Inputs
Inputs
Inputs
• Safety
Safety
Safety Interlock
Interlock
Interlock: This normally open contact works
like a soft emergency stop button. If the ProMix
PD2K reads the input as CLOSED it interrupts
system operation and removes power from the
pumps regardless of the current operating mode.
If the input is read as OPEN, the system operates
normally
NOTE:
NOTE:
NOTE: This digital input is always enabled.
Do not toggle this input to put the system into
Standby mode.
• Gun
Gun
Gun Trigger
Trigger
Trigger #1
#1
#1 and
and
and #2
#2
#2: These normally open
(maintained) contacts provide a signal to the Mix
Units to indicate whether or not a spray device is
triggered. These inputs provide timing for alarm
functions and also drives the flow control algorithm.
If an input is OPEN the Mix Unit operates as
though the spray device is off. The input must
be maintained CLOSED to signal that the spray
device is triggered.
NOTE:
NOTE:
NOTE: The Gun Trigger discrete inputs must be
enabled individually via
,
on the ADM. If it is set to ‘Network’ the discrete
input is ignored and the spray device trigger signal
is handled via the network communications.
If enabled, it is imperative that this signal be sent
any time the spray device is triggered. Without the
signal, the flow control features will not work.
Analog
Analog
Analog Inputs
Inputs
Inputs
Flow
Flow
Flow Control
Control
Control Set
Set
Set Point
Point
Point #1
#1
#1 and
and
and #2
#2
#2: When enabled,
these 4-20 mA signal inputs are used to set and
adjust the operating flow control set point for each
Mix Unit. The ProMix PD2K scales the set point
linearly from 0 to the Max Set Point setting (see
).
Examples
,
• In
In
In Flow
Flow
Flow Control
Control
Control Mode:
Mode:
Mode: If the Max Set Point is 500
cc/min, a 4mA signal is 0 cc/min and a 20mA signal
is 500 cc/min.
• In
In
In Pressure
Pressure
Pressure Control
Control
Control Mode:
Mode:
Mode: If the Max Set Point is
500 psi, a 4mA signal is 0 psi and a 20mA signal
is 500 psi.
NOTE:
NOTE:
NOTE: The Flow Control discrete inputs must be
enabled individually via
,
on the ADM. If set to ‘Network’ the discrete input is
ignored and set point adjustment is handled via the
network communications.
4–20
4–20
4–20 mA
mA
mA Flow
Flow
Flow Control
Control
Control Set
Set
Set Point
Point
Point Input
Input
Input
Figure 11
PLC (4–20 mA Signal) Mix Unit #2
PLC (4–20 mA Signal) Mix Unit #1
PD2K Discrete Input
O = Output
R = Return
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