Specifications

12
Curtis 1310 Manual, Rev. B
2 — INSTALLATION & WIRING: Wiring
Power connection
The battery is connected to the 1310 controller’s power tabs through a fuse
and a keyswitch. The power tabs are used because there are inductive loads on
the system (Aux Contactor and Proportional Valve coils) which could cause
the current to exceed 3 amps. The fuse is required to protect the wiring, as
the controller could draw significant power if there were a short or failure in
the unit.
The keyswitch is used to “start” the system. Both the B+ power tab and
the B+ signal at J1-24 are used as the Keyswitch Input. When the keyswitch
is closed, the B+/KSI input goes high, the controller powers up, and the BDI
functions are enabled.
Outputs
The system shown in Figure 3 has two high-power outputs and two LEDs that
run off keyswitch power.
The first power output drives a proportional valve coil. Outputs 1 and 2
are special in that they have internal current feedback lines. VCL can use this
signal in a PID loop to regulate current, which is necessary to properly control
the position (and flow) in a proportional valve. Outputs 1 through 4 also run
at a higher frequency and thus can provide a smoother current (less ripple).
The second power output drives a basic contactor coil. It is connected to
Output 2, which has a current feedback signal. In this case, VCL can use the cur
-
rent feedback signal to ensure that the coil is connected and drawing the proper
current when on. In this way, enhanced fault diagnostics can be performed.
Using the PWM outputs to drive the LEDs allows the the brightness of
the LEDs to be varied. The frequency is too high for the human eye to see any
flickering. Note that a dropping resistor must be used because even low duty
cycle PWM applies full battery voltage is short bursts, and this will destroy the
LED without a dropping resistor limiting the current. Note that the internal
impedance to ground of the driver will cause leakage current to flow through the
LEDs even when the output driver is off. Refer to the Digital Output Specifica-
tions (page 15) when calculating the leakage current. This leakage current can
be enough (> 2 mA) to light high efficiency LEDs. Model 1310-5210 provides
two output drivers (Outputs 14 and 15) that do not have leakage current issues
and may therefore be the best suited for driving LEDs.
Switch inputs
All the outputs can be used as active high inputs (On when connected to B+).
There are four special inputs that are active low (On when connected to B-).
If an output is used as an input (see, for example, Input/Output 15 in the
wiring diagram), VCL must take care not to turn on that output or a direct short
to B+ could be established through the switch and the internal FET driver.
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