Flashes Flashes
Hardware defective. Replace the module.• Switch on the CPU and/or the system power
supply modules.
• Verify that the U connectors are inserted.
• Check to see if too many modules are inserted.Supply voltage L+ to module too low or missing Check supply voltage L+.
On
Supply voltage L+ is present and OKChannel disabled. ---
On
Channel configured and OK. ---
On
Channel is configured (channel error pending).
Diagnostics alarm: e.g. wire break
Check the wiring
Disable diagnostics.Analog input module AI 4xU/I/RTD/TC ST supports the following diagnostics and hardware
interrupts.
Diagnostics interrupt
The module generates a diagnostics interrupt at the following events:
● No supply voltage L+
● Wire break
● Overflow
● Underflow
● Common mode error
● Reference junction
Hardware interrupt
The module generates a hardware interrupt at the following events:
● Low limit violated 1
● High limit violated 1
● Low limit violated 2
● High limit violated 2
For detailed information on the error event, refer to the hardware interrupt organization block
with the "RALRM" instruction (read additional interrupt info) and to the STEP 7 online help.
The module channel that triggered the hardware interrupt is entered in the start information
of the organization block. The diagram below shows the assignment to the bits of double
word 8 in local data.If the two high limits 1 and 2 are reached at the same time, the module always signals the
hardware interrupt for high limit 1 first. The configured value for high limit 2 is irrelevant. After
processing the hardware interrupt for high limit 1, the module triggers the hardware interrupt
for high limit 2.
The module has the same reaction when the low limits are reached at the same time. If the
two low limits 1 and 2 are reached at the same time, the module always signals the
hardware interrupt for low limit 1 first. After processing the hardware interrupt for low limit 1,
the module triggers the hardware interrupt for low limit 2.tructure of USI = W#16#0001
Data block name Contents Remark Bytes
USI
(User Structure Identifier)
W#16#0001 Additional interrupt info for hardware interrupts
of the I/O module
2
The channel that triggered the hardware interrupt follows.
Channel B#16#00 to B#16#n Number of the event-triggering channel (n =
number of module channels -1)
1
It is followed by the event that triggered the hardware interrupt.
Event B#16#03 Low limit violated 1 1
B#16#04 High limit violated 1
B#16#05 Low limit violated 2
B#16#06 High limit violated 2A diagnostics alarm is output for each diagnostics event and the ERROR LED flashes on the
module. The diagnostics alarms can, for example, be read from the diagnostics buffer of the
CPU. You can evaluate the error codes with the user program.
Table 5- 5 Diagnostics alarms, their meaning and corrective measures
Diagnostics alarm Error code Meaning Solution
Load voltage missing 11H Supply voltage L+ of the module is