Calibration Procedure - Elektro-Automatik PS 9000 1U Betriebsanleitung

4.3 Calibration (readjustment)
4.3.1 Preface
The devices of series PS 9000 1U feature a function to readjust the most important output values when doing
a calibration and in case these values have moved out of tolerance. The readjustment is limited to compensate
small differences of up to 1% or 2% of the max. value. There are several reasons which could make it necessary
to readjust a unit: component aging, component deterioration, extreme ambient conditions, high frequent use
In order to determine if a value is out of tolerance, the parameter must be verified first with measurement tools of
high accuracy and with at least half the error of the PS device. Only then a comparison between values displayed
on the PS device and true DC output values is possible.
For example, if you want to verify and possibly readjust the output current of model PS 9080-100 1U which has
100 A maximum current, stated with a max. error of 0.2%, you can only do that by using a high current shunt with
max. 0.1% error or less. Also, when measuring such high currents, it is recommended to keep the process short,
in order to avoid the shunt heating up too much. It is furthermore recommended to use a shunt with at least 25%
reserve.
When measuring the current with a shunt, the measurement error of the multimeter on the shunt adds to the error
of the shunt and the sum of both must not exceed the max. error of the device under calibration.
4.3.2 Preparation
For a successful calibration and readjustment, a few tools and certain ambient conditions are required:
• A measurement device (multimeter) for voltage, with a max. error of half the PS's voltage error. That measure-
ment device can also be used to measure the shunt voltage when readjusting the current
• If the current is also going to be calibrated: a suitable DC current shunt, ideally specified for at least 1.25 times the
max. output current of the PS and with a max. error that is half or less than the max. current error of the PS device
• Normal ambient temperature of approx. 20-25°C
• Warmed up PS unit, which has been run for at least 10 minutes under 50% power
• An adjustable load, such as an electronic load, which is capable of consuming at least 102% of the max. voltage
and current of the PS device
Before you can start calibrating, a few measures have to be taken:
• Let the PS device warm up in connection with the voltage / current source
• In case the remote sensing input is going to be calibrated, prepare a cable for the remote sensing connector to
DC output, but leave it yet unconnected
• Abort any form of remote control, deactivate master-slave mode, set device to U/I mode
• Install the shunt between PS device and load and make sure the shunt is cooled somehow
• Connect external measurement device to the DC output or to the shunt, depending on whether the voltage is
going to be calibrated first or the current
4.3.3

Calibration procedure

After the preparation, the device is ready to be calibrated. From now on, a certain sequence of parameter calibra-
tion is important. Generally, you don't need to calibrate all three parameters, but it is recommended to do so.
Important:
When calibrating the output voltage, the remote input "Sense" on the rear of the device has to
be disconnected.
The calibration procedure, as explained below, is an example with model PS 9080-100 1U. Other models are
treated the same way, with values according to the particular PS model and the required load.
EA Elektro-Automatik GmbH
Helmholtzstr. 31-33 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
PS 9000 1U Series
www.elektroautomatik.de
ea1974@elektroautomatik.de
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