Maintenance
10.2 Fail‐Safe Operation
The Fail‐Safe system is designed to alert the operator and provide a safe output in case of any system failure. Basically, it is designed to shutdown the process in the event of a set‐up error, system error, or a failure in the sensor electronics.
The Fail‐Safe circuit should never be relied on exclusively to protect critical heating processes. Other safety devices should also be used to supplement this function!
When an error or failure does occur, the display indicates the possible failure area, and the output circuits automatically adjust to their lowest or highest preset level. The following table shows the values displayed on the LED display and transmitted over the 2‐way interface.
Symptom | Error Code | Priority |
Heater control temperature over range | ECHH | 1 (high) |
Heater control temperature under range | ECUU | 2 |
Internal temperature over range | EIHH | 3 |
Internal temperature under range | EIUU | 4 |
Temperature under range | EUUU | 5 |
Temperature over range | EHHH | 6 (low) |
Table 9: Error Codes in 1‐Color Mode (FA models)
| Condition |
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| Priority |
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| (wide band)** |
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| (narrow band)** |
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| Heater control temperature over range |
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| ECHH |
| ECHH |
| ECHH |
| 1 (high) |
| ||||
| Heater control temperature under range |
|
| ECUU |
| ECUU |
| ECUU | 2 |
|
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| Internal temperature over range |
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| EIHH |
| EIHH | EIHH | 3 |
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| Internal temperature under range |
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| EIUU |
| EIUU |
| EIUU | 4 |
|
| ||||
| Wide band detector failure |
|
| EHHH |
| EHHH |
| <temperature> | 5 |
|
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| Narrow band detector failure |
|
| EHHH |
| <temperature> |
| EHHH | 6 |
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| Energy too low |
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| EUUU |
| <temperature> |
| <temperature> | 7 |
|
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| Attenuation too high (>98%) |
| EAAA |
| <temperature> |
| <temperature> | 8 |
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| Attenuation too high >95% |
|
| <temperature> |
| <temperature> |
| <temperature> | 9 |
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| ("dirty lens", relay will go to “alarm” state) |
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| EUUU | <temperature> |
| <temperature> | 10 |
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| EHHH |
| <temperature> |
| <temperature> | 11 |
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| <temperature> |
| EUUU | <temperature> | 12 |
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|
| <temperature> |
| EHHH | <temperature> | 13 |
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|
| <temperature> |
| <temperature> |
| EUUU | 14 |
|
| ||||||
|
| <temperature> |
| <temperature> |
| EHHH |
| 15 (low) | |||||||
*only available through RS485
**Wide and narrow band stands for the first and the second wavelength in
Table 10: Error Codes in 2‐Color Mode (FR models)
46 | Marathon Series FA/FR |