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PS 9000 1U Series
3.5.4 Remote control via the analog interface (AI)
3.5.4.1 General
The built-in, up to 1500 V DC galvanically separated, 15-pole analog interface (short: AI) is on the rear side of the
device offers the following possibilities:
•
Remote control of current, voltage and power
•
Remote status monitoring (CC/CP, CV)
•
Remote alarm monitoring (OT, OVP)
•
Remote monitoring of actual values
•
Remote on/off switching of the DC output
Setting the
three
set values via the analog interface always takes place concurrently. It means, that for example
the voltage can not be given via the AI and current and power set by the rotary knobs, or vice versa.
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 put in operation. Analog set values can be fed in by an ex-
ternal voltage or generated by the reference voltage on pin 3. As soon as remote control via the analog interface
is activated, the values displayed will be those provided by the interface.
The AI can be operated in the common voltage ranges 0...5 V and 0...10 V in each case 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 and is then:
0-5 V
: Reference voltage = 5 V, 0...5 V set values (VSEL, CSEL, PSEL) correspond to 0...100% nominal values,
0...100% actual values correspond to 0...5 V at the actual value outputs (CMON, VMON).
0-10 V
: .Reference voltage = 10 V, 0...10 V set values (VSEL, CSEL, PSEL) correspond to 0...100% nominal values,
0...100% actual values correspond to 0...10 V at the actual value outputs (CMON, VMON).
Input of excess set values (e.g. >5 V in selected 5 V range or >10 V in the 10 V range) are clipped by setting the
set value at 100%.
Before you begin, please read these important notes for use of the interface:
•
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 since KE firmware version 2.03
•
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 input, such as VSEL, CSEL and PSEL, must not be left unconnected (i.e. floating)
•
It is always required to provide all three set values at once. In case any of the set values is not used for adjust-
ment, it can be tied to a defined level or connected to pin VREF (solder bridge or different), so it gives 100%
The analog interface is galvanically separated from DC output. Therefore do not con-
nect any ground of the analog interface to the DC- or DC+ output!
3.5.4.2 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. 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.
3.5.4.3 Acknowledging device alarms
Device alarms (see
) are always indicated in the front display and some of them are also reported as signal on
the analog interface socket (see
), for example the overvoltage alarm (OV), which is considered as critical.
In case of a device alarm occurring during remote control via analog interface, the DC output will be switched off
the same way as in manual control. While alarms OT and OV can be monitored via the corresponding pins of the
interface, other alarms can’t. Those could only be monitored and detected via the actual values of voltage and
current being all zero contrary to the set values.
All device alarms (OT, OV, PF, OCP and OPP) have to be acknowledged, either by the user of the device or by the
controlling unit. Also see
„3.6.2. Device alarm handling“.
Acknowledgement is done with pin REM-SB switching
the DC output off and on again, means a HIGH-LOW-HIGH edge (min. 50ms for LOW), when using the default
level setting for this pin.
