PTS 400.3 PLUS Operation Manual_R02 Page 236/306
16. Verification of accuracy of PRS 600.3
The reference standard used for the calibration of the PRS 600.3 should be of a higher class (class
0.01).
If a reference standard of the same class 0.02 is used, the own errors regarding the actual calibration
certificate of the standard and calculated uncertainty must be regarded.
To check the correct functioning of the instrument it is enough to verify active energy measurement in
3 phase 4 wire mode.
Preparation
Test setup
Example test setups for calibration of the PRS 600.3 with a 3-phase or a single-phase reference
standard and a 3-phase or a single-phase source can be found in chapter [17.2.22].
The AC power source (SRC), the reference standard (REF) and the error evaluation unit (EEU) are
shown as function blocks. At modern reference standards, normally the blocks REF and EEU are
combined in one instrument.
Follow the instructions in the operation manuals of the used instruments for the blocks SRC, REF,
EEU and adapt the connections where necessary.
Note: The voltage neutral bridge cable to connect the black sockets of U1, U2, U3 must be placed
during all energy measurements (single phase and three phase).
Precautions to minimize the influences of the test setup
• Ground the voltage circuit at exactly one point (connect N to PE), preferably at the Reference
standard.
• Take the supply of the instruments from the same point (e.g. the same distribution socket).
• Use well defined wiring (route cables of same phase together, twist cables)
• Keep ambient conditions stable (temperature, humidity etc.)
• Let the instruments warm-up before use (at least 1 hour).
• Use a measuring frequency either synchronized to line frequency (50 / 60 Hz) or explicitly differ-
ent (e.g. 53 / 63 Hz).
• Use a power source with good stability and signal quality (pure sinus wave form)
Connection of PRS 600.3 Impulse Output to Impulse Input of error evaluation unit
To perform the energy comparison method one of the impulse outputs (LEMO 5-pole: Pin 3 = Im-
pulse signal (5V), Pin 4 = GND) must be connected to the impulse input of the error evaluation unit or
directly to the reference standard, if the error evaluation unit is integrated in the reference standard.
An adapter cable LEMO 5-pole to BNC socket and a standard BNC to BNC cable to connect directly
to reference standards with BNC inputs can be ordered at MTE.
- Adapter cable LEMO 5-pole to BNC socket (H1K Z00 9B0 670 101)
- BNC impulse cable 2m (H0K 51R G58 U02 020)
Some reference standards, which use low ohm pull-up resistors at their impulse inputs (e.g. Radian
standards), are not working directly with the impulse output of the PRS 600.3, which is equipped with
a 1k series resistor to protect the output.
To drive this type of inputs with low ohm pull-up resistors a level adaptation with a NPN transistor
switching to ground must be used. Such an adapter can be ordered at MTE:
- Level adaptation MTE devices Radian devices (H 2 2431 0755)
General information needed to process requests/orders for impulse adapters/cables
A) Impulse cables between own instruments (EMH / MTE / EDI / HEG / L&G)
• Instrument types, impulse connectors and impulse direction
(Instrument A. Output x to Instrument B. Input y)
• Divider factor (10:1, 100:1, 1000:1), if divider function is needed
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