Why do I get FP Error 33437?

Question

I sometimes get Error 33437 "The specified module was sent a Power Up clear command: FP write.vi" This error occurs in the middle of a test when a LabVIEW vi attempts to take a 4-20 mA reading from a pressure sensor. We are using FP-1000 Network, FP-RLY-420 relay and FP-AI-1000 analog input modules. The communications to the relay module seem to work OK. The message is generated only occaisionally - not everytime the AI module is accessed.

Answer 1

I am placing this answer on the original post because I am providing a detailed description on why a Power Up Clear warning occurs, even though I will address some of the comments as well.
First of all, in answer to one of the comments, modifying the watchdog timer will have no effect on a Power_Up Clear Expected warning response.
An FP-1000/1001 module will return a warning response "N00" on several occasions following power first being applied to the unit or power being reapplied to the unit. The first communication directed specifcally at the network module, and at each I/O module on the bank, if it is not the power up clear command "A", will return "N00" which means that a power up clear was expected. The first command to the module, even if not a power up clear (resulting in the warning) is treated as a power up clear command so that subsequent commands execute normally. The power up clear expected will be return for each I/O module on the bank when it is first addressed.
If the Power up clear expected warning is problem for you on a daily or repetitive basis, you can write an initalization routine for your program, that starts of with a read from each module on the system, discard the warnings, then starts the main portion of your program.
Alternatively, if you are using the Optomux Command set (with either the FieldPoint-Optomux VI's or your own programming), make sure that you send the Power Up Clear command to each module at the start of the program. For example, to send a power up clear to a network module at address 0, you would send the command ">00A??[lf][cr]" where [lf][cr] is a line feed/carriage return and the ?? means to ignore the checksum. Alternatively, the checksum variation is ">00AA1[lf][cr]". To send the command to module address 4, it would be ">04AA5[lf][cr]".
Franck, the fact that you see the Power Up Clear Expected command as a normal occurance throughout your operation indicates that your module is continually being reset. I would put a scope on your power supply lines because you likely have a very noisy DC signal.
Regards,
Aaron