Noise while measuring analog inputs through a SC-2311

[TJ Culliton]

I recieve high amounts of bleed over voltage on adjacent channels when measuring voltage input through a 5B-40 module into a 6052E DAQ card. Do any connectors need to be shorted out? Could there be a ground loop? All devices are configured as NRSE.

[MuraliRavindran]

There may a number of reasons causing the bleed over voltage and the main reason being the amplifier settling time. Use the links(two links) below and it explains the theory behind as well as possible solutions. Please do let me know if you have any more questions. Have a great day. Since the links are too long they sometimes break into more than one line, make sure to copy all the lines in continuity. http://ae.natinst.com/operations/ae/public.38c4500dc10862567a100753500/5b86a63ecc0d48828625629800571743?OpenDocument http://ae.natinst.com/operations/ae/public.nsf/fca7838c4500dc10862567a100753500/48cc15b99e99f87886256297005f69a8?OpenDocument

[fraffan]

I have a similar problem. I have an SC-2311 with a 5B40-2 module. I have a shielded thermocouple cable connected directly to the +- screw terminal and the shield is connected to the analog ground on the board. When I take measurements on the open thermocouple, I get a flat signal as expected, but once the thermocouple cable moves around for repositioning, for example, I get a strange osscilatory behavior (sometimes a square wave, sometimes a sine wave) in my signal. This oscillation is definitely triggered by cable motion, but sometimes it becomes permanent so immobilizing the cable won't help at all. As you can expect, this osccilatory behavior is also present when the thermocouple cable is connected to an actual thermocouple. Does anybody know what may be causing this behavior on the signal? I think it may have somthing to do with the +- screw terminals themselves since the problem persists among 3 channels on the board and on 2 different 5B40 modules.