Recent content by willpoll

Are you sure of the density at 508 kg/m3?

A+ and B- in RS485 do not equate to transmit and receive as in RS232. You were able to receive in one direction because of the similarity between signal levels on the 485 TX- and 232 RX. From: http://www.piclist.com/techref/io/serial/rs232.htm

As stated, you already have an AB PLC talking to 3 of the devices, have it poll the remaining devices and if necessary add another Prosoft module and have the BMS poll the PLC for whatever information it needs. This assumes two things - (1) that the PLC can use multiple Prosoft modules and...

Has this installation ever worked correctly, or is this a new installation?? If new, likely the phase rotation and order of the varying gensets are not the same as each other or the utility. Synchronization can only take individual generators so far out of native phase and frequency to meet...

That would really depend on the Slave PLC. But my guess would be that generally it would return a 0. Unless you are mapping a 32-bit float to 400002, then I'd expect half of the 32-bit word. I would expect an address error unless the Slave PLC requires specific definition of all Modbus...

Great work, hats off to you for putting forth the effort. A good Modbus book is sorely needed. Despite all the hype, we all know Modbus is far from dead. -Will

What's the device? I've found some that are confusing, at least to me. They refer to address 44001 which makes you think its holding register at address 4001, when in reality it is offset 44001, in other words in modscan you have to poll 84001. -Will

Charz: Sorry if this is too obvious, but you didn't mention that you have Modscan connecting through the appropriate com port. The default port for Modscan is probably 1, which will almost definitely be incorrect. Look in device manager under Ports (Com and LPT) to determine the correct...