Yesterday I observed a few techs working on a pretty old (~20 years) Rosemount 1051 with old firmware. They were having a (possibly) unrelated issue where the DCS cannot read the HART digital variables after upgrading some hardware so they were checking to see if the transmitter was sending digital variables at all (4-20mA primary variable was working just fine).
A TREX was hooked up and they saw that they could not configure the HART digital variables (old firmware) but they could read sensor temp and other items that were obviously coming across via HART. To narrow down the reason for being unable to configure the variables to the communicator or transmitter, theydecided to hook up a laptop with AMS on it to the transmitter to see if theycould access those settings. As soon as the laptop was hooked up, the boiler feed pump theywere standing next to tripped (suction pressure transmitter on a running feed pump). The readout on the laptop was the expected value (~80 psig) but the DCS was now reading ~25 psig. When the laptop was disconnected from transmitter, the transmitter reading in DCS jumped from 25 psig to what the laptop was reading.
The laptop was connected using some sort of USB device with banana plugs and hook clips that were connected to the transmitter terminals (parallel to DCS).
Any ideas?
A TREX was hooked up and they saw that they could not configure the HART digital variables (old firmware) but they could read sensor temp and other items that were obviously coming across via HART. To narrow down the reason for being unable to configure the variables to the communicator or transmitter, theydecided to hook up a laptop with AMS on it to the transmitter to see if theycould access those settings. As soon as the laptop was hooked up, the boiler feed pump theywere standing next to tripped (suction pressure transmitter on a running feed pump). The readout on the laptop was the expected value (~80 psig) but the DCS was now reading ~25 psig. When the laptop was disconnected from transmitter, the transmitter reading in DCS jumped from 25 psig to what the laptop was reading.
The laptop was connected using some sort of USB device with banana plugs and hook clips that were connected to the transmitter terminals (parallel to DCS).
Any ideas?