Building Automation Knowledge Base

Issue Can I run an anti-virus software on an I/NET host? Environment I/NET Site Cause Anti-Virus on Host PC? Resolution Yes, but I/NET must be shut down, with all associated drivers, during the virus scans. Also, have the anti-virus shut down when installing I/NET on the PC.

Issue Error code 2041 when reading a SNVT from a TAC Xenta 103 Environment TAC Xenta 103 Cause Bindings may have been made with LonMaker after the device was created in TAC Vista. The wrong address is referenced in TAC Vista. Resolution Error code 2041 means no answer from the TAC Xenta unit. Invalidate the addresses in TAC Vista Reread the addresses for the unit using status window for the unit.

Issue Can I connect a thermistor to a TAC Xenta 471? Environment Xenta 471 I/O module Thermistor sensor Cause Xenta 471 does not have any thermistor inputs. Resolution TAC Xenta 471 has 8 analog inputs that can be set up as current inputs (0/4-20mA with external power and 4-20 with internal power) or as voltage inputs (0-1, 0/2-10 V DC). 

Issue Why does I/NET require all other software to be shut down during installation? Environment I/NET Site Cause Why does I/NET require all other software to be shut down during installation? Resolution It is not just I/NET that this makes a difference on. Any software install process can be disrupted or have errors induced, if other items are running or starting in the background of the PC. The problems can range from files being copied with errors, to certain files not being copied at all. It is a good practice when installing any software, to end task on all applications except windows.

Issue What is a node? Environment I/NET Site Cause What is a node? Resolution A node is a device, connected to a network, which can communicate with other nodes, using a common protocol, be addressed (having a unique identification and perform calculations) and/or exchange data with other nodes.

Issue What is the limit of nodes on a segment? Environment I/NET Site Cause What is the limit of nodes on a segment? Resolution There can be up to 64 nodes in a segment under optimal conditions(FTT-10A and TP/XF-1250) or 128 (LPT-10). Two segments can be connected by the use of a repeater, but are still one channel.

Issue Why not assign global or indirect points to an MR? Environment I/NET Site Cause Why not assign global or indirect points to an MR? Resolution If you do, anytime your sublan has communication problems, they will often cause problems on your controller lan. Another problem is that point values from indirect points to not pass through some MR-DDC modules.

Issue What is DLA? Environment I/NET site Cause DLA Explanation Resolution DLA stands for Distributed Link Architecture. It is a software package, that is an addition to I/NET 2000, which provides the ability to have more than 100 NPRs in a given system by sharing link numbers among them. It is explained in TCON 297.

Issue What I/NET 2000 revisions work with DLA? Environment I/NET Site Cause What I/NET 2000 revisions work with DLA? Resolution I/NET 2000 rev 2.12 and above work with DLA. It also contains and requires NPR bin file rev 1.10.

Issue How can I use global and indirect points with MRs/ASCs? Environment I/NET site Cause How can I use global and indirect points with MRs/ASCs? Resolution Assign them to an address in the SLI that is unused by any MR or ASC. Then use a calculation on the point in the MR to get the value from the indirect point. (Or put the calc on the global point to get the value FROM the external MR point.)

Issue Can I modify the SNMP name or address on an NPR? Environment I/NET site Cause Can I modify the SNMP name or address on an NPR? Resolution If the customer has an SNMP manager on site and wants to use this function, enter the information he gives you. If not, leave them alone. If the address gets set to 0.0.0.0, you will have communication problems across a commercial router.

Issue Why not enter more than one reference host in a host or NPR configuration? Environment I/NET site Cause Why not enter more than one reference host in a host or NPR configuration Resolution Because if someone brings in an NPR to a site which has been used before, it will contain all of the IP addresses and links from the previous site. If any host or NPR on site refers to it as a reference host, those addresses may get spread to all of the hosts/NPRs on site. More than one reference host will make it tricky to get rid of the erroneous addresses. Besides that, the system doesn't need more than one.

Issue Calculate conversion coefficients for a PWM output Environment I/NET Resident I/O Editor PWM output Cause The key fact to remember is that the counts (in the built in calculator) are no longer counts but "ticks" or .01 seconds. The second key fact is that the A/D converter has NOTHING to do with this process. It only applies to voltage or current outputs, not pulsed outputs. Resolution If your minimum pulse is a tenth of a second you would enter counts low as 10. Full pulse is 5.2 seconds, 520 for counts high.

Issue How do I calculate conversion coefficients for a PI input? Environment I/NET site Cause How do I calculate conversion coefficients for a PI input? Resolution B will always equal 0. M will be the power factor assigned by the power company (or the manufacturer of the meter such as Veris.) So if you're told that each pulse is .305 KWh, your M is .305. Veris' 6000 series are configurable from .005 to 1 KWh per pulse. The exception to this would be a dual contact meter. In that case, they may alternate between contacts for each pulse. Therefore, you would double the power factor for your M since you're only reading half of the pulses.

Issue How can I clear the memory of an MR? Environment MR Cause If an MR with a database is given a new address using the dip switches, the DDC, I/STAT parameters and points remain in its memory. Resolution The only way truly clear the memory is to use an I/STAT or M/STAT: Enter the service mode Re-enter the address or communication speed. Changing these parameters can work but be careful not to leave the speed at anything other than 9600. Refer to the I/STAT instructions in TCON 126 or TCON 130 for instructions on service mode operations.

Issue How can I clear the memory of an ASC? Environment I/NET site Cause How can I clear the memory of an ASC Resolution Turn on dipswitches 6-12 and cycle power. Turn them back off and cycle power again. According to the instructions, this should do it but a few times, I've had to do this twice in a row.

Issue What does the disable light on a controller mean? Environment I/NET site Cause The disable light indicates an error in the controller. Resolution If the disable light is on, the controller is totally inoperable and cannot be fixed.  You must ship it for repair.

Issue What does the test light on an MR mean? Environment I/NET site Cause What does the test light on an MR mean? Resolution If it's on solid, the controller is ok. Flashing constantly - database problem, clear memory and start over. Other flashing patterns mean that various devices on the board have failed and it will need factory repair.

Issue What are termination resistors used for? Environment I/NET Site Cause What are termination resistors used for? Resolution As the signal travels down the cable, it sees a characteristic impedance (AC resistance). The closer it gets to the end of the wire, the higher the impedance goes until it gets to the end where it reaches infinity. Ohms law..so the voltage signal goes up and causes a reflected signal back up the wire at a lower energy level. This can be seen by the controllers as noise and if the timing is right, can disrupt communication. The timing and reflected signal level are functions of the cable length. Using termination resistor presents the signal with a consistent impedance and clamps the reflection. (They're also referred to as clamping resistors.)

Issue How do I install termination resistors? Environment I/NET site Cause How do I install termination resistors? Resolution They must be installed at each end of the lan. Keep in mind that if you have a stub (tee) near what you think is the end of the lan which is very long, the stub (or what you thought was the stub) is really the end. Anyway, the resistor is installed between the signal wires. In other words, one end goes into terminal one of the controller/tap/NPR along with the positive signal wire and the other end goes in terminal 2 with the negative wire. If you have a controller lan separated by a repeater or FOIs, it should be treated as 2 lan segments and each of them terminated at the repeater or FOI as well.