Download Frequency Generator

Frequency Generator
When it comes to track guidance of driverless vehicles, inductive systems are the most reliable. In
order to fulfil the demands of various applications, many generators have been developed.
The frequency generator HG 57500YD generates
an AC current in a conductive loop for track guiding Automated Guided Vehicles (AGV).
The board in Eurocard format hosts two independent generators with power amplifiers and a
transformer for dc-decoupling. Its frequencies
are stored in an internal EPROM and may be selected using either the 16 position HEX switch or
an external controller (i.e. PLC). The generator
has minimal power dissipation and a high efficiency factor due to its Class-D power amplifier.
Dimensions
HG 57500YD
Both loop currents undergo voltaic conversion
through a different transformer, are therefore separately adjustable and are set to give a constant
output level. Short circuit and circuit breaks will
be detected and indicated by the LEDs on the
front panel.
The generator HG 575 is
compact and cleanly built. It
was constructed to be particularly easy to service.
Contrary to its extensive performance, the frequency
generator HG 575 definitely
has an extremely low price
which conforms to the “Low
cost“ AGV concept.
Reading Antenna
Interpreter
Generator
HG 57500
Route cable
Sketch
Induktive Guidance Systeme
with Frequency Generator
LED
Meaning
24V
Shows operating voltage
Z<Zmin
Short circuit or load impedance too low
(Generator 1 / 2)
O.K.
Correct / Precise load impedance
Z>Zmax
Breach of wire or load impedance too high
(Generator 1 / 2)
F1, F2
Frequency Selection
Strom 1, 2
Loop Current Adjustment
Mon. 1, 2
Test sockets for loop current adjustment
(Generator 1 / 2)
Frequencies
Freq.-Sel.-Inputs
Switch
Frequency
[Hz]
The frequencies shown below are set as standard
into the device. Others can be preset on request.
F8
F4
F2
F1
0
0
0
0
0
1
1
0
0
0
1
5000
2
0
0
1
0
5100
3
0
0
1
1
5200
4
0
1
0
0
5700
5
0
1
0
1
6000
6
0
1
1
0
6300
7
0
1
1
1
6500
8
1
0
0
0
7000
9
1
0
0
1
7500
16 frequencies are pre-programmed into the device and saved on the EPROM. Any of these 16
frequencies may be directly accessed by using
the hex selector on the front of the device. It is
also possible to select a frequency using the device interface. In order to adjust the frequency by
frequency- select- inputs, the rotary switch for the
corresponding generator has to be set to zero.
The levels for these inputs are defined as follows:
(the input impedance is approx.10 kOhm):
A
1
0
1
0
7800
-
log.
Zero
0 to 0.8 Volt or open
B
1
0
1
1
8000
-
log.
One
5 to 24 Volt
C
1
1
0
0
8500
Synchronization
D
1
1
0
1
9000
E
1
1
1
0
9500
F
1
1
1
1
10000
If both generators on one card are set to the same
frequency then the frequencies are generated
synchronously and in phase.
Loop current long/short [mA]
30/60
Magnetic field
The frequency generator HG 575 has two independent and freely selectable channels. Each
channel offers a range of settings from 5 to 10
kHz in steps of 1Hz.
Dimensions and LEDs
Frequency Generator
HG 57500YD
Loop Current and Impedance
-
Long loop Impedance
3 to 100 Ohm
Short Circuit or Loop Breakage
-
Short loop Impedance
1 to 30 Ohm
Low load impedances are indicated by the red
LED „Z< Zmin. Contact resistances in terminal
boxes add to the overall impedance in such a
way that short circuits within the application may
not be detected. High load impedances will be
detected as an interruption and are indicated by
the red LED „Z>Zmax“. Within the normal load
range the green LED shows „O.K.“. The detection
area depends on the outputs selected as well as
on the current adjusted.
In short loops the loop current may be up to
60 mAeff. For long loops the maximum current
amounts to 30 mAeff. The distinction between
long and short loops does not refer to the actual
length but to the selected connectors.
For loop currents up to 30 mAeff loops of any
length up to an impedance of 100 Ohm can be
connected to the outputs „Loop closure long“
and „Loop start“.
For currents higher than 30 mAeff the outputs
„Loop closure short“ and „Loop start“ are to be
used. In this case the maximum impedance for a
current of 60 mAeff is 30 Ohm.
For load impedances higher than 100 Ohm the inductive reactive component can be balanced by
a capacitor which has to be assembled on the
board. In this case the loop must be connected to
the output „loop closure long balanced“. The capacity of the capacitor has to be determined separately for each application.
Loop Current Adjustment
An AC voltage measuring unit is to be connected
to each test socket on the front panel. This measures the voltage drop of the conductor current
over a 1 Ohm resistance. Therefore the device
has to have an AC range from 0 to 60 mV for currents to be set from 0 to 60 mA and a frequency
range higher than 10 kHz. The current can be adjusted separately at the corresponding spindle
potentiometer for each generator with a small
screw driver.
Load impedance range and preset power output
for connections to the loop closure:
LED
Color
Short (I = 30 mA)
Long (I = 60 mA)
LED Z<Zmin
Red
—
1 to 3 Ohm
LED O.K.
Green
1 to 30 Ohm
3 to 100 Ohm
LED Z>Zmax
Red
> 30 Ohm
> 100 Ohm
Load Impedance Ranges
For a correct detection of loop breakage and
short circuit the actual current to be adjusted as
well as the scale of the impedance should be
known in order to set the generator accordingly.
Stacking in Variant HG 57500RD
Version HG 57500RD is capable of stacking:
Both generators on a card can be connected in
series. Precondition is, that both generators use
the same frequency. With stacking a loop can be
supplied with double impedance.
Technische Daten
- Dimensions
Eurocard, 30.48mm
- Connector
DIN 41612, C 32 pin, AC supply
- Power source
24 V ±10 %
- Power consumption
Less than 0.3 A, using both channels
- Load Impedance
3 to 100 Ohm at 30 mA with large loop
1 to 30 Ohm at 60 mA with small loop
- Output current
max. 30 mA with large loop
max. 60 mA with small loop
Others variants than 30/60 mA available on request
- Operating temperature
0 to 50o C
- Output frequencies
Selectable from 5 to 10 kHz
- Resolution
1 Hz
- Frequency accuracy
Quartz stabilised to better than 0.02 %
- Adjustment options
Either with the rotating switch or an external input
(Frequency choices preset in EPROM)
Date: 15.11.2011
English, Rev. 02
Author(s): RAD/SIS