Hi all, This is my first post so I hope I cover everything and appreciate any responses. I've worked on AB systems for years but until now, never tried to commission any. I'm just assembling a test rig for flex modules using an old 503 in a 7 slot rack with a 1747-SN scanner. So, I've got an ASB (rev E) with 2 OB16s, an IB16 and an IE8 (Ser B). Reading the manuals for the SN, ASB and IE8 I've got everything but the analogue working. I'm using the PLC 5 ladder suggestions from the manual for the BTR and BTW but something doesn't seem to be right. Channel 0 seems to be working as 4-20mA (as I want) but the other 7 do nothing. I think the problem is the 'Data File' from the BTW because when I sent two words (both -256), all eight channels seem to function. I could leave it like that but I don't have faith that they're correctly configured as I clearly don't understand how it works. The manual reads as if the data sent to configure the module is all on one word, and the example ladder seems to to concur. I assume I'm being stupid but can anyone point out how and where please? I greatly appreciate any help. John