Allen Bradley ControlLogix DHRIO 18F1 or 28F1 Error


Our setup:
Windows 2003 R2 server
Ignition 7.6.4 32 bit
AB drivers 1.6.4(b2013112117)

Most of our PLC’s on site are AB SLC504 and these form many individual DH+ networks in up to 6 seperate buildings. We’ve connected to these networks using a controlLogix gateway mainly comprising of an Ethernet card and a DHRIO card but one gateway has an L65 CPU in each of the buildings and they’ve been stable for a long time but we’re now experiencing this problem on differant gateways.

I’ve been in touch with Rockwell Tech support who are looking at the problem and have some tech notes on these error codes but they don’t help but they’ve brought up the question of Ignition’s AB drivers and the problem may be that.

I was wondering if anybody else had seen this issue before and could give me some guidence?

How fast and often are you scanning tags? You may be choking the DH+ system. I saw this type of problem myself and had to turn my scan rates to slower settings.


We’ve got a frontline DH+ analyser and we’re not overloading the DH+ networks, although Rockwell have given us an engineering tool to grab all of the memory registers when this next occurs so hopefully that will shed some light on to what’s actually happening.

Error 18F1:
1 = Channel A
8 = DH+ Interface Task
F1 = Connection-related fault

Most likely one of the DH+ nodes you are trying to connect to from Ignition is offline?

What we had to do disconnected and reconnected one Channel A DH+ node at a time both physically and also within Ignition. Long story short, we found that as soon as we disabled one node (that wasn’t connecting to the machine) in Ignition, the problem went away and all is now well with both channels and the 1756-DHRIO card. i.e. Via RSLix under module statistics 0 transmit retries exhausted, 0 timeout w/no ack’s received in the counter tool.

Lesson learned here is that if we have a machine with a SLC 5/04 being polled for data by Ignition via DH+ through a 1756-DHRIO card, if it (the machine) gets powered off or moved to another DH+ channel – we will start seeing the 1756-DHRIO statistics for transmit retries exhausted and timeout w/no ack’s received counters increase and eventually the card will fault out, requiring intervention for a reset.


I forgot about this thread until recently but it was sorted out after we contacted Rockwell about this and with some special logging tools that they gave us, they traced the fault to the firmware and issued a firmware update, once we’d flashed the card, the problem was solved.