Open Wire Diagnostics; Digital Outputs; Interface To The Cpu - Siemens SIMATIC S5 Manual

Operation

3.1.5 Open Wire Diagnostics

With thermocouples, the module performs open wire diagnostics for the analog inputs 0...12
and 15.
To do this, a brief test current is sent to the measuring loop and measured.
Depending on the configuration, the diagnostics can activate an emergency and switch over to
an alternate thermocouple, an alternate Pt 100, or a sensor.
Open wire diagnostics are automatically disabled when the characteristic curve linearization is
de-activated.

3.2 Digital Outputs

There are 17 outputs available for outputting the manipulated variables. The outputs are short-
circuit-proof and protected against interference voltage. LEDs on the front panel indicate the
states of the output stages (see Chapter 2.2.2 for connector pin assignments of the X4 connec-
tor).

3.3 Interface to the CPU

Communications with the CPU is performed according to the bus specifications that are valid
for SIMATIC S5 systems. The temperature controller occupies 32 bytes of the CPU address
space. Writing a message frame number (0 ... 63) permits 64 different data block message
frames of 31 bytes each to be transferred to or from the CPU module (see message frame
structure). Thus, 2048 bytes are available in the transfer RAM on the module for transferring
parameters or measured values.
The FB 162 function block is available for configuring and handling the module.
The address code can be selected as S5 bus (PESP' + 8 address lines) or PESP + 12 address
lines (addressing socket J77). In S5, data transfer can be done using byte or word commands.
The sequence of high byte and low byte is irrelevant.
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IP244B
C79000–B8576–C865–01