AMETEK MX Series Rev: AY - Manual (Page 170)

User Manual - Rev AV AMETEK Programmable Power
MX Series 170
6.4 Routine Output Calibration
For best results, it is recommended to perform the measurement calibration procedure first. See
section 6.3. The MX Series I has more calibration coefficients than the MX Series II. Where
relevant, this is indicated. On Series II models, the output calibration screens will show only
available cal factors.
Follow the steps outlined in this section to perform a routine output calibration. Note that each
available output range (except -HV and -XV options) has its own output calibration coefficients
and must be calibrated. If a range is not available on the system configuration you have (e.g.
MX45-1 or MX45-3 without -R option), skip to the relevant output range
. Table 6-3 shows the
individual calibration points in a summary format. The following text is a more detailed
explanation of the procedure.
The full-scale calibration should be done in the AC and DC mode for both the low and high range
if available. The option -HV range can be done only if the high range (300VAC) is not available. If
both the standard high range and the -HV or -XV optional ranges are available, calibrate the
standard range.
Note: Selecting the calibration screen (by entering the Cal Password) will turn off the ALC mode.
Conversely, turning on the ALC mode will turn off the Calibration mode. If the ALC mode is
turned off during calibration, the cal password will have to be re-entered to allow calibration.
Setup:
Connect the test equipment to the power source depending on model configurations as shown in
Figure 6-1and Figure 6-2. Setup for an MX60, MX90 or an MX135 configuration is similar to that
shown in Figure 6-2 with the master sense terminal block used for external voltage sense. For
multi-phase systems, each phase has to be calibrated individually. Note that no load is required
for most output calibrations.
DC Offset measurements:
If the DMM used to perform DC offset calibration has trouble rejecting AC noise in VDC mode
(measurement not stable), it may be necessary to use a small filter circuit at the output of the
amplifier to measure the DC offset. A 100Kohm RN60 1/4W (CI P/N 560131) and 22uF, 35V (CI
P/N 611267) series network can be used in this case as shown below. Use this circuit only while
performing DC offset checks and remove for other calibrations.
High Low
AMPLIFIER
OUTPUT
DMM
VDC
Pos Neg
100 Kohm 22 uF
Figure 6-4: DC offset AC filter