11 - Specification
45
QPX750 Instruction Manual
11.2
Meter Specifications
Display Type:
5-digit (Volts), 4-digit (Amps), 4.3” TFT colour.
Voltage
Resolution 1mV
Accuracy: 0.1% of reading ± 2 digits
Current
Resolution 10mA
Accuracy: 0.3% of reading ± 2 digits
V x A:
Resolution 0·1W
Accuracy: 0·5% ± 0·1W
V/A:
Meter shows calculated nominal V/A value; 5-digit resolution.
11.2.1
LOGIC CONTROL INPUT and OUTPUT
LOGIC IN is a rear-panel opto-isolated input that is activated at an input current greater
than approximately 1mA. User can set LOGIC IN (via the keyboard) to enable the output,
disable the output, or be ignored when it is activated.
LOGIC OUT is an isolated rear-panel open-collector output that will sink up to 2mA when
activated (‘switch closure’); the maximum voltage that can be applied to LOGIC OUT is
30VDC. User can set LOGIC OUT to be ‘closed’ or ‘open’ for output enabled or disabled,
current limit (CC mode), power limit (CP mode), or for any fault trip.
11.2.2
ANALOG REMOTE CONTROL and MONITORING
Quasi-analog inputs and outputs to set voltage and current limit and to monitor actual
output voltage and current. The control inputs are read four times per second by the
A-D converter and the output is set according to the selected input scaling; similarly, the
monitor outputs are updated four times per second with values representing the actual
output voltage and current. These signals each have a range of 0 to 10V or 0 to 5V with
respect to the shared COM return signal; the set range applies to all inputs and outputs.
Analog Control Voltage Range:
Keyboard selectable to be 0 to 10Vdc or 0 to 5Vdc for range
maximum output. Absolute maximum input 20Vdc.
Analog Control Accuracy:
Voltage: 0.3% ± 4mV; Current: 0.5% ± 40mA.
Analog Control Common Mode Range:
± 2.5Vdc max to negative output.
Analog Control Input Impedance:
Nominally 40k
Ω
.
Analog Monitor Voltage Range:
Same as set for Analog Control Voltage Range.
Analog Monitor Accuracy:
Voltage: 0.3% ± 4mV; Current: 0.5% ± 40mA.
Analog Monitor Output:
Connect to isolated measuring system with >10k
Ω
input
impedance. Will withstand a short-circuit.
11.2.3
KEYBOARD & ROTARY CONTROL
All functions, including the selection and set-up of the remote-control interfaces, can be set
from the keyboard. The rotary Jog control can be used to adjust output voltage and current
settings in a quasi-analog mode.
Voltage Programming
Speed (Typical figures)
Maximum time required for output to settle within 1% of its total excursion
(for resistive load). Excludes command processing time:
90% Load
No Load
90% Load
No Load
80V 9.4A
Up
200ms
200ms
Down
60ms
190ms
12V 50A
Up
190ms
190ms
Down
10ms
160ms