7-58
Chapter 7. PARAMETER SETUP
[Resistor type]
When driving an SSR by voltage time-proportional output, the out-
put voltage of the controller must be within the input rated voltage
(optimum ignition voltage) of the SSR.
On the
DCP31
, a newly developed variable output system is utilized
that enables output of the optimum ignition voltage even when driv-
ing two or more SSRs.
This system sets the optimum current value on the controller so that
the optimum ignition voltage with respect to the internal imped-
ance of the SSR side can be obtained.
The following shows equivalent circuits and related formulas:
• Description of Symbols
(1) Details
I
O
: Setting output current of controller (setting range: 2
to 22 mA)
V
O
: Maximum applied load voltage (approx. 14.7V)
V
SSR’
: Actual input voltage to SSR
V
SSR
: Input rated voltage range of SSR (V
SSR/MIN
to
V
SSR/MAX
)
V
SSR/MIN
: Minimum input rated voltage of SSR
V
SSR/MAX
: Maximum input rated voltage of SSR
Z
: Internal impedance of SSR
V
D
: Internal voltage drop of SSR (normally 1 to 2V)
(2) Equivalent circuit when one SSR is connected
Formulas (1) and (2) formulas must be satisfied.
(1) formula V
SSR/MIN
≤ I
O
× Z + V
D
≤ V
O
(2) formula V
SSR'
< V
SSR/MAX
(V
SSR'
= I
O
× Z + V
D
)
DCP31
SSR
+
–
+
–
I
O
(V
O
)
V
SSR'
Z
V
D
