>>Message imported from previous forum - Category:Communications Products << User: mchartrand, originally posted: 2018-10-25 15:00:01 Id:217 This is a re-posting from the obsoleted (October 2018) "Schneider Electric Telemetry & SCADA" forum.
**_JoeWaZoo: Hello, I am trying to use some Banner Engineering Data Radios with a ScadaPack 357 controller but am having some comms issues. The Banner device only uses Unsigned Words whereas I am being told that the ScadaPack uses only Signed Words and therefore the two systems will not talk. Is it possible to create a Tag in ScadaPack that is a unsigned Integer that I could map to a 40001 Modbus Holding Register on Slave #1? Thanks,_**
There may be some confusion here. SCADAPack controllers comply with the Modicon Modbus standard. Holding registers are defined as 16-bit registers. Data in these registers may be displayed (in TelePACE) as either signed, unsigned, signed double, unsigned double, floating point or binary. Data is not necessarily stored in a signed or unsigned format. It is simply stored and it is up to the user to decide how to view it. For example, a register that is viewed as a floating point type is actually made up of two 16-bit registers. If you were to view the two registers separately as either a signed or unsigned type you would see totally different values, yet when viewed as a floating point type it shows the proper value. It essentially comes down to what the binary value of the register is. For the most part, values for signed and unsigned contain identical binary strings as long as the value is positive. Obviously an unsigned register cannot contain a negative value. I don't think you'll have a problem as long as the radios are able to work with the protocol. SCADAPack 357 controllers support the following protocols:
Serial: Modbus RTU, Modbus ASCII, DNP
LAN: Modbus/TCP, Modbus RTU in UDP, Modbus ASCII in UDP, DNP in TCP, DNP in UDP
Let me know if you have any further questions regarding this by emailing me at technicalsupport[at]controlmicrosystems.com. Thank you.