Operator`s manual

Signametrics 24
2.13.4 Source DC Current Measure DC Voltage
 Sensing: Selectable, at source terminals or sense inputs (remote)
 Range: 10nA to 12.5mA
 Voltage Measurement range: 0 to
2.4V
Range Compliance Voltage [1] Resolution [2] Minimum
level
Accuracy 23C  10C One Year
1.25 A
4.2 V 500 pA
10 A 1% + 10 A
12.5 A
4.2 V
5 A 50 A 1% + 100 A
125 A
4.2 V
50 A 100 A 1% + 500 A
1.25 mA 4.2 V
500 A 1 A 1% + 5 A
12.5 mA 1.5 V
5 A 10 A 1% + 50 A
[1] Compliance voltage is the range at which the current source is linear. It does not imply a measurement range. Wile in this
mode, the DMM measures the load voltage ranging from 0V to 2.4V.
[2] Resolution without Trim DAC. The use of the Trim DAC can improve the resolution by a factor of 10, but it has to be set
separately since it is not calibrated.
2.13.5 Pulse Generator
 Settable Negative and Positive Pulse widths: 25us to 3s
 Resolution: 1
s or 100s
 Amplitude range: settable 0 to
10V

Pulse Base level: 0V

Modes: 1 to 32,000 burts of pulses or continuous.

Requires driver version 1.60, and Microcode version 1.29 and higher.
Parameter Range Typical Resolution
25s to 65.5ms 1s
Positive and negative
pulse widths
65.5ms to 3s
100s
Number of Pulses 1 to 32,000 1
Amplitude 0V to +10V or 0V to -10V 5mV
2.14 Accuracy Notes
Important: all accuracy specifications for DCV, Resistance, DCI, ACV, and ACI apply for the time
periods shown in the respective specification tables. To meet these specifications, Self Calibration must
be performed once a day or as indicated in the specification table. This is a simple software operation that
takes a few seconds. It can be performed by calling Windows command DMMCal(), or selecting S-Cal in
the control panel.
These products are capable of continuous measurement as well as data transfer rates of up to 20,000
readings per second (rps). In general, to achieve 7-1/2 Digits of resolution, the Aperture should be set to
0.5s or a higher value. 6-1/2 digit resolution requires at least 10ms Aperture. For 5-1/2 use at least 625us
Aperture.
Since the DMM is powered via a USB calbe (AM/BM 6’ cable), it is important to make sure it gets the
required 5V supply. Using the right USB cable is very important. Make sure this cable has a 24 AWG
wires for power supply, indicated by marking on the cable such as 28/1P + 24/2C. Be aware that there are
a lot of cables which are marked 28/1P + 28/2C. These have high resistance, and will not be adequate.
Another issue can be with powered USB hubs. Some of the lower quality units can have upwords of 8V
rather than the required 5V +/-5%. On initialization (DMMInint) the DMM measures its internal supply
voltage and returnes an error or warning code if the power is inadequate. See DMMGetSupplyV function.