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EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
PSB 9000 3U Series
3.6.4
Remote control via the analog interface (AI)
3.6.4.1
General
The built-in, galvanically isolated, 15-pole analog interface (short: AI) is on the back side of the device offers the
following possibilities:
•
Remote control of current, voltage, power and resistance
•
Remote status monitoring (CV, DC terminal)
•
Remote alarm monitoring (OT, OVP, PF, OCP, OPP)
•
Remote monitoring of actual values
•
Remote on/off switching of the DC terminal
Setting the
three
set values of voltage, current and power via the analog interface must always be done concur-
rently. It means, that for example the voltage can’t be given via the AI and current and power set by the rotary
knobs, or vice versa. The internal resistance set value can additionally be adjusted. Contrary to manual adjustment
or via digital interface, the analog interface doesn’t offer separate set values of power and current for the source
and sink mode.
Analog set values can be supplied by an external voltage or generated from the reference voltage on pin 3. As
soon as remote control via the analog interface is activated, the displayed set values will be those provided by the
interface. The AI can be operated in the common voltage ranges 0...5 V and 0...10 V, both representing 0...100%
of the nominal value. The selection of the voltage range can be done in the device setup. See section
for details. The reference voltage sent out from pin 3 (VREF) will be adapted accordingly:
0-5 V
: Reference voltage = 5 V, 0...5 V set value signal (VSEL, CSEL, PSEL, RSEL) correspond to 0...100% rated
value (exception:
R
Min
...R
Max
for resistance) and 0...100% of the actual values correspond to 0...5 V at the actual
value outputs CMON and VMON.
0-10 V
: Reference voltage = 10 V, 0...10 V set value signal (VSEL, CSEL, PSEL, RSEL) correspond to 0...100%
rated value (exception:
R
Min
...R
Max
for resistance) and 0...100% of the actual values correspond to 0...10 V at the
actual value outputs CMON and VMON.
Input of excess signals (e.g. >5 V in selected 5 V range or >10 V in the 10 V range) are clipped by the device by
setting the corresponding set value to 100%.
The OVP set value and other supervision (events) and alarm thresholds cannot be set via the AI and therefore
must be adapted to the given situation before the AI is going to be in control.
Before you begin, please read these important notes about the use of the interface:
After powering the device and during the start phase the AI signals undefined statuses on the
output pins, such as ALARMS 1. Those must be ignored until is ready to work.
•
Analog remote control of the device must be activated by switching pin “REMOTE” (5) first. Only exception is
pin REM-SB, which can be used independently
•
Before the hardware is connected that will control the analog interface, it shall be checked that it can’t provide
voltage to the pins higher than specified
•
Set value inputs, such as VSEL, CSEL, PSEL and RSEL (if R mode is activated), must not be left unconnected
(i.e. floating) during analog remote control. In case any of the set values is not used for adjustment, it can be tied
to a defined level or connected to pin VREF (solder bridge or different), so it gives 100%
•
Switching between sink and source mode can only be done with the voltage level on pin VSEL. Also see example
.
The analog interface is galvanically isolated from the DC terminal. If not absolutely necessary, do
not connect any ground of the analog interface to the DC- or DC+ on the DC terminal.
3.6.4.2
Resolution and sample rate
The analog interface is internally sampled and processed by a digital microcontroller. This causes a limited resolu-
tion of analog steps. The resolution is the same for set values (VSEL etc.) and actual values (VMON/CMON) and
is 26214 when working with the 10 V range. In the 5 V range this resolution halves. Due to tolerances, the truly
achievable resolution can be slightly lower.
There is furthermore a max. sample rate of 500 Hz. It means, the device can acquire analog set values and states
on digital pins 500 times per second.
