Dear Sir,
In our facilities, we have several units of Datataker, namely DT80G-3 and DT85-3, used in structural health monitoring activities of bridges and other large structures.
One of the DT80G-3 suffered the effect of lightning (we deduce), and some components broke, which completely shut down the device.
We have already replaced the DC-DC converters U165 and U166 and the unit has started working. However, the test identified a fail in VANA. We noticed that there is a short circuit between the output of U183 (positive output), the output of U103 (negative output) and ground, which prevents the correct operation of the DC-DC U158 and DC-DC L13. After de-soldering U183 and U103, the VANA test is OK.
I think U183 and U103 are used to power the vibrating wire interface. Since we are not planning to use vibrating wire sensors, we can leave it as is for now.
TEST report generated at 1989/01/01,00:00:51
dataTaker 80 Version 9.18.6291 Flash 2015/08/07 14:28:13
Product: DT80G-3
Serial Number: 097234
VEXT 19.3 V
VBAT (6V) 0.00 V FAIL
IBAT +26 mA PASS
VSYS 7.05 V PASS
VLITH (3.6V) 3.60 V PASS
VDD (3.3V) 3.26 V PASS
VANA (3.8V) 3.33 V PASS
VRELAY (4.5V) 4.80 V PASS
VREF (2.5V) 2500.00 mV PASS
Ics I 0.20000 mA PASS
Ics II 2.5000 mA PASS
Vos diff 0.0 uV PASS
Vos 3W I 0.0 uV PASS
Vos 3W II 0.0 uV PASS
Vos shunt 0.0 uV PASS
Vos + 0.0 uV PASS
Vos - 0.0 uV PASS
Vos 0.0 uV PASS
Vos # 0.0 uV PASS
Vos diff atten 0.0 uV PASS
Vos + atten 0.0 uV PASS
Vos - atten 0.0 uV PASS
Vos atten 0.0 uV PASS
Term. factor 1.00000 PASS
Shunt (100R) 100.000 Ohm PASS
dataTaker 80 E30 - Analog measurement fault
CMRR 0.0 dB FAIL
Overall health FAIL
This is the answer when we execute a voltage measurement command:
DT80> 5+hV
dataTaker 80 E30 - Analog measurement failure
5+HV not yet defined V
Does anyone have any advice for resolving the CMRR problem identified by the test routine?
Could the problem be in the ADC?
Thank you very much in advance.
