File: SG524_r3eng - April 2017 - Technical note: SG 524 page 7 of 16
PM 250
SG 524
The reset of the Alarm is done by setting the Enable command
OFF for two seconds.
In absence of alarms the power supply may be left in “Ready”
continuously: when it receives the enabling command (ON) it
enters into “MW-ON” state and generates output power, when
the enabling command is removed (OFF) the unit comes back
to “READY” state
.
Working Modes
The behavior of the SG 524 depends on its “working status”:
it has several statuses with different meaning and functiona-
lity. The logic flow of these statuses is showed on the next
power on:
when the unit is switched on, during the first two
seconds, the unit runs the bootloader, waiting for any serial
firmware update data. After that, if there are not alarms, the
unit goes in Ready status, otherwise it goes in Alarm status if
an alarm is present. It is a temporary status at Power On.
ready:
it’s a waiting state. The unit waits for the enabling
command to generate microwave.
The unit may last in this state as long as needed: it exits auto-
matically in case of alarm. It goes to next “MW-ON” status
when the enabling command is set ON and the reference
signal is > 1%
mw-on:
starts microwave emission at the presetted power
level.
The unit exits from this mode in case of:
* the enabling command is set OFF: enters into Ready state,
or
* the reference signal goes below the 1%: enters into Ready
state,
or
* ALARM presence: the unit goes to Alarm status
alarm:
when an alarm condition is present the unit will
remain in this status. To exit from Alarm the Enabling com-
mand must be set OFF for 2 seconds and the alarm condition
should be removed.
There is an exception. Due to the characteristic of the alarm,
the “Power Supply Undervoltage” alarm needs a switch off of
the unit in order to be reset. See Alarm Troubleshooting table
at page 15 for the complete alarm list and relative codes.
Meaning of external commands.
LINE BREAKER 0-1: in pos. 1 the unit goes in POWER ON.
The line switch can be freely switched off at any time.
POWER SET: it’s an analog input value and has the meaning
of “desired percent” of the full output power (450W)
When this value is lower than 0.2 Vdc the unit does not gene-
rate any output power, when over that threshold it generates
microwave power proportional to this signal value (at the
condition Enable signal is ON).
The scaling is 45W/V. It can be controlled:
- by the knob located in the front panel during the manual
mode;
- via usb serial connector, with the dedicated software, in
remote mode;
- via fieldbus module in remote mode (for SG 524 vers. 1
only);
- by an analog signal (0-10Vdc) on CONN #2 pin 5 (+), pin
18 (ground), using as voltage source pin 7 (+10 V)
POWER ENABLE: it’s a digital input located on pin 4 CONN
# 2, has value ON/OFF. It must be ON to go in MW-ON
status and generate microwave energy. It can be set OFF at
any time.
OPERATING FREQUENCY:it is a control parameter. It can
be set automatically if the Automatic Tuning is enabled, or
manually otherwise. If the Automatic Tuning is disabled the
frequency can be set
- through the display in manual mode, or
- via software through the USB serial port or the fieldbus
module (the latter option only for SG 524 vers. 1). It can not
be set in external mode using a signal.
AUTOMATIC TUNING: it is a feature of the unit based on a
patented algorithm (US patent 6,020,794).
Due to the possibility to change the operating frequency,
the user can tune his system choosing between two modes.
The automatic tuning can be enabled either by the display
in manual mode or via software in remote mode. Once the
automatic tune is enabled the software performs the algorithm
when the unit goes in MW-ON status and it runs until a status
changing occurs. The goal of this function is to perform a real
time tuning of the load even if it changes continuously.
REVERSE POWER ALARM THRESHOLD: Threshold can
be set by the user in order to limit the reflected power. This
threshold can be set freely by the user, depending on the pro-
cess requirement. The unit can bear a total reflection condition
