Download Power Controller Users Guide

Power
Controller
User´s Guide
Rev./Date:
1.0 / 14 May 2017
Author:
U. Schwendicke
Project:
APE Slow Control
General Description
The APE Power Controller was designed to control the APE power supplies of one rack
(2 crates) either locally by push button or remote via RS232 from an external PC. It is
implemented with an ALTERA Cyclon FPGA controlling two current loops, one for each
power supply. The current loops are powered from a separate 5V-supply voltage and
isolated from the FPGA-part (3.3V supply voltage) by optocouplers. The APE power
supplies are switched on as long as no current flows. This means that, if not powered, the
power controller box should not influence the APE rack.
Functional Description
The functional behaviour of the Power Controller is determined by programming the
FPGA.. The FPGA contains a NIOS-CPU, that runs a small C-program. After power on
and initialization of the FPGA, the power controller enters a state where both APE power
supplies are switched off. The state of the power controller can be observed via 3 LEDs
on the front panel of the power controller box (traffic light) and via RS232 (see chapter
remote control). From the initial state (“APE off”) the power controller can be forced to
enter the “APE on” state either by pressing the push button at the front panel of the box
or by sending a “power on” command via RS232. This transition is implemented in two
steps: At first the master crate is switched on (delivering the clock to the slave) and after
a wait time of 3.2 seconds the slave crate is switched on too. The transition is indicated
by blinking of the green LED. This transition can be stopped manually (e.g. in case of
malfunction of the master power supply) by pressing the push button again (and keep it
pressed until green blinking finished). The “APE on” state is indicated by the green LED.
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Power Controller Users Guide
The transition back to the “APE off” state is similar. It can also be initiated either by
pressing the push button or by a RS232 command. This transition cannot be interrupted
and will be executed immediately after receiving the command. Nevertheless there is
also a dead time of 3 seconds indicated by both (green and red) LEDs off. After that dead
time the red LED is switched on to indicate the “APE off” state.
Remote Control
The remote control protocol is very simple. It is based on three commands that can be
sent from the controlling PC to the power controller box. The PC is the master, the power
controller the slave, that will only answer (send via RS232) when asked.
The following commands are implemented:
COMMAND
ANSWER
ACTION
1
1
Enter “APE on” state if actual state is “APE off”
else do nothing
F
F
Enter “APE off” state if the actual state is “APE
on”
else do nothing
1 if “APE on”
t
Retrigger alive counter
F if “APE off”
<others>
<echo
command>
Do nothing
The command “t” (test) should be periodically executed to know about the state of the
power controller. The execution of this command will be signalized by flashing the yellow
LED once (you already wondered, what it is good for?). In addition there is an alive
counter on the power controller to watch the periodical testing. If no “t”-command is
received within the last 5 minutes, the yellow LED will be switched on permanently.
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Power Controller Users Guide
The RS232-transmission parameters have to be set as follows:
Electrical characteristics
Remote connection:
RS232 without handshake, DB9-connector male
Interface to power supplies: Switched 5V-Signal ; max current: 100mA short protected
Fuse: 250V 200mA TR5 RS-# 226-0535
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