Metrix CX 1651 Manuel De L'utilisateur page 164

Calibrateur multifonctions CX 1651
Connection of a multimeter to be calibrated (voltage range) to the terminals of 140-01 cable adapter
Current ranges
All DC and AC current ranges are connected to calibrator's +I/-I terminals.
If current is drawn from calibrator's +I and –I output terminals, +I and –I output terminals located at
140-41 cable adapter must not be connected simultaneously!
When using the current output under heavy load (10 to 20 A), the runtime is limited to 0 to 60 s. The runtime
depends on the set current and it is controlled by the microprocessor. The user cannot extend the runtime; if
longer runtime is required, the output terminals must be unloaded, some time must elapse (for example1 min.)
and the load can then be connected again.
When feeding 2 to 20 A current to the output terminals, the output voltage must not exceed approx. 1.5 Vef. If
the current induces higher voltage on the load, the calibrator disconnects the output terminals and displays an
error message.
When ammeters are being calibrated using currents over 1 A, it is important to connect the terminals properly,
paying attention both to the calibrator's output terminals and the instrument's input terminals. Excessive contact
resistance can heat up the terminals and cause calibration errors. Excessive and unstable contact resistance has
non-linear characteristic and can distort the output AC current.
It is not recommended to connect non-standard load to the current output. The calibrator is designed to be used
for calibration of ammeters. Output terminals should be loaded with low and real impedance. Although the output
is fitted with fast electronic and microprocessor protection, high capacitance or inductance can lead to
oscillations of output amplifiers and result in damage.
The instrument to be calibrated can be connected either directly to the front panel terminals, or to Opt.140-01
cable adapter. If L terminal of the instrument to be calibrated is not grounded, then calibrator's -U (-I) terminal
should be grounded (GND U ON, GND I ON, see „Setup menu" chapter).
164 Manuel de l'utilisateur