Wheel System - Traction
115
Service Manual – SC1500
Speed Control Communication with the A1 Control Board
There are five “communication” wires that run between the
A1 Control Board
and the
E1 Curtis 1210 Speed
Controller
. Each wire is used to communicate a unique piece of information as listed in the following table.
A1 Control Board
Terminal
Speed Controller
Terminal
Function
Motion Input J3-6
Pin 6 - Brake - (B -)
The
A1 Control Board
provides a positive 24-volt supply
through a resistor and out of
Motion Input J3-6
to a switch on
Pin 6 - Brake - (B -)
in the
Speed Controller
. The
A1 Control
Board
monitors the voltage on the wire between
J3-6
and
Pin 6
.
When the machine is standing still, the switch is open and the
input is “high” or 24 volts.
When the
Speed Controller
operates the wheel drive motor, it
also closes the switch on
Pin 6
to
B -
to let the
A1 Control Board
know that the machine is moving. When the switch on
Pin 6
closes, the voltage on the wire drops to 0 volts.
Inhibit Output J1-7
Pin 12 - Inhibit Input
The
A1 Control Board
uses the inhibit signal to tell the
Speed
Controller
when it is OK to propel the machine.
If the Operator is not standing on the dead man switch or a
direction has not yet been selected, the switch on
J1-7
will
be closed to
B -
. The
Speed Controller
will see a low signal (0
volts) at
Pin 12
.
When the dead man switch is closed and either a forward or
reverse direction has been selected, the switch on
J1-7
opens
and the signal at
Pin 12
becomes high (24 volts) to signal the
Speed Controller
that is it now Ok to propel the machine when
the go pedal is pressed.
B+ B+
B-
Y1
Brake
E1 Curtis
1210 Speed
Controller
ORN
RED/WHT
2
1
RED/YEL
ORN/BLU
BLU/BLK
RED/BRN
Pin 6
Pin 12
Pin 9
Pin 16
Pin 17
BLK
BLK
B-
Brake +
KSI
Pin 14
Pin 5
B+
A1
Control Board
Main Machine
Controller
Motion Input
Inhibit Output
J3-6
J1-7
J3-7
J3-5
J3-3
+ 24v
Inhibit Input
+ 24v
Drive Switch Input
+ 24v
Reverse Alarm
+ 24v
Status Signal
+ 24v
Brake - (B -)
Status (B -)
Reverse Alarm (B -)
B -
Drive Switch Output
B -
