Table of Contents
Advertisement
Design and theory of operation
FUNCTIONAL DESCRIPTION
The Q1 transistor functions as an ON-OFF switch, controlled by the
"Safe Relay" signal from the control unit to the base.
Provisions for independent ON-OFF switching is also made for by
the jumper switch S1-S2-S3. When placing the jumper switch in pos.
2-3, the Q1 transistor will be switched ON.
The IC1 voltage regulator output is monitored by LD1 (Green LED).
The starboard and port signals are connected to IC4 + A and B
optocouplers and will switch on the transistor current when the
rudder command signals switches low, also provided that the
optocoupler diodes are on via limit switches.
The IC4-A and B transistor current will control Q2 and Q5 and thus
switch on IC2 or IC3 solid state switch. The control signals are
monitored by the red and green LED's (LD3 and LD4). The LD3 and
LD4 are connected to the diodes of the optocouplers IC6-A and B,
such that if both should conduct at the same time (PORT and STBD
rudder commands both on), the switch transistor Q3 will be switched
off.
This will result that the safety relay IC5 will deenergize, and no
rudder commands to the solenoids will be made.
During normal operation, the transistor Q3 will be conducting, and
status is monitored by the LD2 LED.
The safety relay IC5 is also controlled by a load protection circuit.
The solenoid current is sensed by the resistor R21 and RV1,
controlling transistor Q6. When Q6 is conducting, the optocoupler
IC6-D will be switched ON, thus switching on the next optocoupler,
IC6-C, that will start to conduct, switching on the Fault indicator
LD5, and make the transistor Q4 start to conduct. The Q4 will start
the diode in IC5 and thus deenergize the safety relay IC5. At the
same time, the IC6-C will be latched to conduct. To reset, the system
must be switched OFF and ON.
The jumper switch marked H/L determines the current through R21
for low (19-40V) or high voltage (110-220V). If the jumper switch is
pulled out, the safety device is disabled. The fuses F1 and F2 are
connected in series with each solenoid.
3-11
20169223D
Advertisement
Table of Contents
