We have thermocouples type K connected to ET200SP module : AI 4xRTD/TC 2-,3-,4-wire HF
6ES7 134-6JD00-0CA1.
We read out values but the values are about 10°C where they should be 20°C.
Our base units for the modules are 6ES7193-6BP20-0DA0 and 6ES7193-6BP20-0BA0.
Do we need instead modules 6ES7193-6BP40-0DA1 and 6ES7193-6BP40-0BA1 (with temperature acquisition), or are the types we have ok for the thermocouple measurement?

Hi DavidBrown,

The Base Unit with "/T" makes easier the reading of the thermocouples because the reference junction temperature is read by an internal temperature sensor on the BaseUnit, but they are not mandatory.

How have you configured the reference junction of the channel of the TC? 

Beyond what has already been said, be sure and use the proper K-type TC connection wiring, preferably shielded K-Type TC cabling.

Depending on the wiring scheme, you may need K-Type TC terminal pairs between the TC and the RTD module.

Refer to the connection diagram for the module so the connection scheme and hardware configuration are matched.

As a related incident, yesterday on an s7-1500 PLC with a S7-1500 TCx8 HF module in a s7-1500 remote IO rack, we were seeing very odd values.  All 8 TC inputs were ~10C low.  We use 2 different TC simulators, 1 of which detected a low impedance and shut down the simulator output.

Today we went to a backup of the same project - saved on Tuesday of this week - and loaded that into the PLC.  The only differences were some additional PLC tags, a few TON timers / DBs, some ladder logic, and we had experimented with various hardware configuration settings in the TCx8 HF module.  Changed the 2 decimal constrained / offset output to default with 1 implied decimal and saved it yesterday, and ever since it was acting incorrectly.

We tried swapping out the HF module, and manually jumping out all 8 TC inputs so they would all read ~ambient module temperature.  They all read ~10C low still.

After restoring from a backup made Tuesday before adjusting the TC module's HW config, it started acting right again.

Very strange behavior.  FYI, TIA Portal Professional V16 upd 4.

I mention that in case you discover something strange that makes no sense.  Try from scratch simply creating a new project, add the hardware and see if the TC module starts behaving for you too.

DavidBrown

We have thermocouples type K connected to ET200SP module : AI 4xRTD/TC 2-,3-,4-wire HF
6ES7 134-6JD00-0CA1.
We read out values but the values are about 10°C where they should be 20°C.
Our base units for the modules are 6ES7193-6BP20-0DA0 and 6ES7193-6BP20-0BA0.
Do we need instead modules 6ES7193-6BP40-0DA1 and 6ES7193-6BP40-0BA1 (with temperature acquisition), or are the types we have ok for the thermocouple measurement?