30
GMC-I Messtechnik GmbH
7.2
Auto-sensing mode
Function
Output voltage values required for voltage measuring and control
circuits can be acquired directly at the consumer instead of at the
output terminals with the help of the SENSE + and SENSE –
sensing lead terminals at the analog interface. Sensing mode
operation (remote sensing) offers the following advantages:
•
In the constant voltage regulating mode, current related
voltage drops occurring in the output leads have practically no
effect on voltage supplied to the consumer. Voltage at the
output terminals is automatically increased to compensate for
voltage drops.
•
In the constant current regulating mode, voltage limiting at the
consumer is independent of output current.
•
Since the voltage value provided by the measuring function is
relative to the voltage value acquired at the sensing leads,
load parameters such as power consumption and load
resistance can be more accurately determined.
The parameters and limit values included in figure 7.2, and in the
chapter entitled “Electrical Data”, apply to operation with the sensing
leads.
Connection
•
The two sensing lead terminals at the analog interface
(SENSE + and SENSE –) must be connected to their
respective output poles at the desired point (generally
speaking as close to the consumer as possible).
•
It is advisable to twist and/or shield the sensing leads in order to
minimize interference (connect shield to the ground terminal of
the negative output pole).
•
Long output and sensing lead impedances may result in
control fluctuations at the output, especially with capacitive
consumers. This effect can be counteracted by connecting
capacitors (CS+, CS-) between the SENSE and output
terminals (see figure 7.2). If the output leads are twisted, their
impedance can be reduced as well.
•
Incorrect connection of the sensing leads does not damage the
KONSTANTER, although it results in the following reversible events:
– Polarity reversal at sensing leads or interrupted output lead:
If output voltage is not being limited at the KONSTANTER
by means of current regulation, it climbs to well above the
selected value which finally triggers overvoltage protection
and immediately deactivates the output.
– Interrupted SENSE + lead:
Voltage between the output terminals increases by
approximately 15%.
– Interrupted SENSE – lead:
The sensing terminals are deactivated (automatic return to
local sensing).
If the sensing leads have been connected incorrectly, rising
voltage between the output terminals is not acquired by the
measuring function.
Cs+, Cs-
= 10 μF to 220 μF
Us+, Us-
1 V
Is+
U
outS
/ 180 k
Is–
0.3 mA
Figure 7.2
Connecting the Consumer for Sensing Mode Operation
Activation
•
The remote sensing mode function is activated automatically after
the SENSE – terminal has been connected to the corresponding
output pole.
•
The function is deactivated once again by interrupting this
connection.
7.3
Status Signal Outputs
Function
•
The KONSTANTER is equipped with three digital open
collector outputs for indicating status.
– Two floating outputs
SIG 1
, SIG 2
and
– One with reference to AGND:SIG 3 +
•
The device status or event to be indicated is independent for
all three signal outputs.
Selection is made by setting the following functions:
– SEtUP/dPYIF/AnIF/SiG-1 txt,
– SEtUP/dPYIF/AnIF/SiG-2 txt and
– SEtUP/dPYIF/AnIF/SiG-3 txt
(see chapter 6, “Menu Structure” and chapter 7, “Operating
Commands”).
•
As a status signal for monitoring devices
•
For controlling external output relays
Application
•
Triggering of certain device functions can be synchronized by
means of connection to the trigger inputs of other
KONSTANTERs.
Connection
•
Values for connection –
Max. switching voltage: 30 V DC
Max. switching current: 20 A
•
If you want to use the signal outputs to send status signals to
external monitoring devices, pull-up resistors must be used in
order to achieve appropriate levels.
The status signal outputs can be connected to the + 15 V
terminal with pull-up resistors (at least 1 k
), in order to
generate an active high signal of + 15 V.
Figure 7.3
Wiring Examples for Status Signal Outputs
PSP-KONSTANTER
Einstellung
USET = Usoll
ISET = Isoll
OUTPUT ON
SEtUP/dPYIF/AnIF/SiG-3
txt
Analog Interface
TRG 1 +
1
TRG 1 -
2
TRG 2 +
3
TRG 2 -
4
SIG 1 +
5
SIG 1 -
6
SIG 2 +
7
SIG 2 -
8
SIG 3 +
9
AGND 2
10
+15V 11
AGND 1
12
Uext +
13
Uext -
14
Iext +
15
Iext -
16
U MON
17
I MON
18
SENSE +
19
SENSE -
20
+OUT
- OUT
Rpu
Usig
Summary of Contents for P1500
Page 68: ...68 GMC I Messtechnik GmbH ...
Page 71: ...GMC I Messtechnik GmbH 71 ...
