OEM Controls SB25 User Manual

SB25 USER’S MANUAL

1 General Information

1.1 SB25 Controller

The SB25 is an environmentally hardened, software controlled, valve drive board.
It receives inputs from rotational sensors (Digisensors), switches, pulse type inputs
(tachometers), and other transducers and directly operates inductive loads such as
proportional PWM electrohydraulic valves, digital (on/off) loads, and loads requiring a
proportional analog voltage. Each output signal may be independently fine-tuned and
calibrated with the hand held Optimizer.

The SB25 has removable connectors for power, inputs, outputs, and Optimizer
connections. These connectors are designated “BT1” through “BT8”. All inputs and
outputs have an associated LED for diagnostic use. In addition, 4 system diagnostic
LEDs are provided for board operation status. A custom cover label identifies the
customer defined name for each of the active inputs and outputs. This cover label also
shows the pinout for each connector and identifies the function of each diagnostic LED.

The SB25 Controller is a versatile and flexible control device. It is custom factory
programmed by OEM Controls Inc. to perform the required control function. A few
examples of its flexibility include:
 Single or dual coil proportional valves with PWM frequencies from 33Hz to 250Hz.
 Single or dual axis joysticks.
 Digital inputs for High/Low ranges, start-up interlocks, output enables, etc.
 Auxiliary outputs for dump valves, alarms, multiplexed output selection, etc.
 User defined “belly” curves to modify the joystick’s output characteristics.

The SB25 is supplied with factory default settings (such as maximum output, threshold,
and ramp time) for the electrohydraulic valves used. However, the customer may select
custom default settings and adjustment limits. Factory programmed data allows the SB25
to be installed and ready to use as delivered. Please contact OEM Controls Inc. for
details on customizing the SB25 Controller for your particular application.

2 I/O

The SB25 has multiple I/O (input/output) options. The number of each type of I/O is
configurable by OEM Controls, Inc.

2.1 Inputs

2.1.1 Digisensor Inputs

The Digisensor is a rotational sensor that converts joystick or rotary handle movement
into an electrical signal. The Digisensor requires only two wires and can transmit its
signal to an SB25 controller up to 500 feet away.

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Two wires connect the Digisensor to the system. The Digisensor’s Red wire connects to
the +12Vor +24V system power, and the Black wire connects to one of the SB25’s
Digisensor Inputs.

Two red diagnostic LEDS mounted on the Digisensor indicate its position (whenever
power is applied). The “Direction A” LED turns on when the potentiometer shaft is
turned counter-clockwise, and the “Direction B” LED turns on when rotated clockwise.
When the Digisensor’s shaft is centered (turned halfway between its ends of rotation)
both LEDS will be on. The section titled “Troubleshooting - Digisensor” presents
additional details.

The Digisensor Inputs on the SB25 are designed to verify the integrity of the Digisensor
signal. Digisensor signals with improper voltages, currents, or timing are rejected and
that Digisensor Input is considered to be off.

Since the Digisensor is a bi-directional sensor, one sensor can control two proportional
outputs, one for each direction.

2.1.1.1 Contactless Digisensor

An additional type of available Digisensor is the Contactless Digisensor. The Contactless
Digisensor’s output signal is identical to the standard digisensor. The Contactless
Digisensor has a non-contacting magnetic Hall Effect internal circuit for increased
rotational lifetime. The Contactless Digisensor’s signal and operation is identical to the
standard digisensor. The only connection difference is that the Contactless Digisensor
requires a third wire. The third wire is Yellow and is connected to system ground (0V)

2.1.2 Local Digital Inputs

Digital Inputs are inputs that have two states, ON or OFF. A Digital Input is driven to the
ON state by applying battery voltage. The OFF state is attained by either applying
ground (0V) or when an open circuit occurs at the digital input. Therefore, an input with
no applied voltage is OFF.

2.1.2.1 Inverted Digital Inputs

A special type of Digital Input available on the SB25 is the Inverted Digital Input. An
Inverted Digital Input is like a standard Digital Input except an Inverted Digital Input
with no applied voltage is ON.

2.1.3 Pulse Type Inputs

Pulse Type Inputs are used to count the rate of an input signal. Pulses per second are
counted and are used by the software to control an output. A pulse is measured on the
transition of the input signal from ground or open circuit to battery voltage. The SB25
can accurately monitor a Pulse Type Signal of up to 700 pulses per second.

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2.1.4 Analog Inputs

Analog Inputs are used to measure an external DC voltage in the 0-5V range. Also, this
input can function as a PLC type 4 – 20mA input because the input circuitry was
designed such that a DC input voltage of 5V results in 20mA of input current.

2.1.5 RS485 Communication ( Remote Inputs )

Inter-board communications between the SB25 and other OEM Controls, Inc. SB family
boards such as the SB10 or Digiplexor is accomplished with the RS485 communication
port. Typically, Digital Inputs on a remote board, such as the SB10 or Digiplexor, are
used to control Digital Outputs on the SB25 through the RS485 communication port.

2.2 Outputs

2.2.1 Output Protection

SB25 PWM and Digital Outputs utilize “smart” FET based power transistors that provide
excellent protection against electronic hazards inherent to mobile applications. These
outputs have over voltage, overload, over temperature and short circuit protection. In
addition, they are protected against limited ESD (Electro Static Discharge) and reverse
battery events.

2.2.2 PWM Outputs

Outputs can be configured to drive proportional PWM inductive loads. A PWM Output
will cycle from ON to OFF at a predefined rate (frequency) required by the PWM load.
The percentage of time that the PWM Output is ON is referred to as the Duty Cycle. The
Duty Cycle is varied to control the load. Typically, the Digisensor rotary input sensor
provides the input for one (unidirectional) or two (bi-directional) PWM Outputs.

2.2.2.1 Diode Clamping

A diode clamp is used to limit the back EMF of an inductive PWM load to one diode
drop below ground. This type of clamping is typically used for high current PWM loads

2.2.2.2 Zener Clamping

Certain inductive PWM loads require a very negative back EMF level. A Zener
Clamping configuration is available for all PWM Outputs.

2.2.3 Digital Outputs

Loads that attain an ON or OFF state due to the state of one or more inputs are referred to
as Digital Outputs. Digital Outputs do not cyclically change state but are typically
controlled by inputs. Inductive loads connected to Digital Outputs are clamped and do
not require additional external clamping.

2.2.4 Analog Outputs

Low current analog voltage outputs can be configured to drive high impedance loads that
require voltages in the range of 0-10VDC.

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2.3 I/O allocation

See the SB25 specifications to determine the number of each type of I/O that can be
allocated on one SB25. There is a maximum number of each type of I/O. Also, some I/O
channels can be configured multiple ways. This leads to a high degree of flexibility for
the SB25 but must be considered when determining the I/O capacity of the SB25.

3 Optimizer

The Optimizer is a hand held user interface with a keypad and an alphanumeric display.
It is used as a calibration and diagnostic tool for display of various system values, and to
make adjustments to the SB25 Controller.

3.1 Optimizer Connection

The Optimizer is connected to the SB25 through the BT1 connector. Refer to the board
cover label for the location of BT1.

3.2 Optimizer Operation

When an Optimizer is connected to the SB25 and a Digisensor Input (joystick) is
operated, the Optimizer display will indicate the status of the active input. The active
channel or function is identified using the customer defined name, and the actual output
value (in %Duty Cycle) is displayed. As the input is varied, the displayed value will
change. If more than one input is operated at the same time, so that several outputs are
active, the Optimizer display will show the channel who’s input was most recently
moved.

There are five adjustment select keys: Threshold, Maxout, Low Range, Ramp Up and
Ramp Down. These keys are used to select one of these 5 parameters to adjust.

The Direction Select key toggles (alternates between) the A and B direction. This key
only functions when all joystick controllers are off. The Optimizer automatically selects
the direction when a joystick is operated; this makes active adjustments easy to perform.

The Function Select chooses one output channel for adjustment. This key only operates
when all controllers are off. Each time this key is pressed, the next function (or channel)
is selected, that is 1 ... 2 ... 3 ... 4 ... 1 ... etc. The Optimizer automatically selects the
function (channel) whenever a joystick is operated, making active adjustments easy to
perform.

3.2.1 Diagnostic Menus

Diagnostic and system information is available with the Menu key. After pressing the
Menu key, the Enter key is used to step through all menu items. Available information
through the menu includes OEM part number, serial number, status for individual I/O
channels, Digisensor counts, etc.

Status for I/O channels provides useful troubleshooting information. Due to space
constraints, the identifier for each I/O channel uses OEM Controls, Inc. name rather than

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