Analog Value Representation For Measuring Ranges With Simatic S7 - Siemens SIMATIC Distributed I/O ET 200eco PN Operating Instructions Manual

I/O device analog input/analog output
10.1 I/O device analog input
thermocouples. The α value conforms to the standards EN 60751, GOST 6651, JIS C 1604
and ASTM E-1137.
The M12 compensation connector is delivered unassembled. You can connect a
thermocouple by using terminals 2 and 4 of the M12 compensation connector.
The M12 compensation connector is bolted to the round socket X1 on the connection
module CM IO 4 x M12 (torque: 1.5 Nm). The procedure is identical to the M12 connector
(see section Mounting (Page 21)).
NOTE
The M12 compensation connector is only designed for the electronic module
8 AI RTD/TC 8xM12. Operation without a cable is not permitted in order to comply with
degree of protection IP67.
• Dynamic Ref. Temp.: The reference junction temperature is measured via a module on a
different station.
With this type of compensation the reference junction temperature (compensation
voltage) is measured by means of an external module on another station.
The reference junction temperature is transferred from the CPU to the I/O device
8 AI RTD/TC 8xM12 by means of the data record DS2 using the SFB 53.
An separate reference junction temperature can be assigned by means of the the user
program to each channel for which you select this type of compensation.
• Fixed Ref. Temp.: The reference temperature is specified permanently.
With this type of compensation, the reference junction temperature is stored as a
parameter.
The reference junction temperature is specified in the parameter "Reference temperature
for TC".
The possible value range is listed in the table Reference temperature for TC (Page 186-
187).
The parameterized reference junction temperature is valid for all the channels of the I/O
device for which you have selected this type of compensation.
10.1.5

Analog value representation for measuring ranges with SIMATIC S7

Representation of analog values
With the same nominal range, the digitized analog value is the same for input and output
values. Analog values are represented in two's complement.
The following table shows the representation of analog values of the analog input.
Table 10-6 Representation of analog values (SIMATIC S7 format)
Resolution
Bit number
Significance of the bits
176
Analog value
15 14 13 12
14 13 12
Sign 2 2 2
11 10 9 8 7
11 10 9 8 7
2 2 2 2 2
Operating Instructions, 06/2022, A5E01250250-AN
6 5 4 3 2
6 5 4 3 2
2 2 2 2 2
1 0
1 0
2 2
ET 200eco PN