Frequently Asked Questions
Q: How many furnaces can be controlled with 1 serial connection?
Between 1 and 8 furnaces if they can share the serial line. That mean all their temperature controllers have RS485 communication module, the same serial frame format and the same baudrate. If the temperature controller communication module is based on RS232 then only 1 furnace.
Q: How many instances I need and how many computers?
One instance of the control application can control between 1 and 8 furnaces connected to 1 or several different serial ports, an instance being able to handle multiple serial ports. The number of instances necessary is dependent of the number of furnaces you have and their localization. For example if you have 10 furnaces and they can be all connected to 1 computer then you need 2 instances and 1 computer, but also 2 computers can be used if some of the furnaces will be connected to the second computer. In another example if you have 5 furnaces in the same location (so they all can be connected to the same computer) then you need 1 instance running on 1 computer. But if those 5 furnaces are located in different locations and is not practical to lay down a serial cable between these locations, then you need 2 computers (one in every location) and 2 instances (one running on each computer), even if in this case you have less than 8 furnaces.
Q: How many instances can be run on the same computer?
A computer can run multiple instances of the control application. The maximum number of instances is limited by the serial ports available (every instance require at least 1 serial port), and by the parallel processing capability of the computer CPU (number of cores). In the worst case when the instances are fully loaded (they have all 8 furnaces working at the fastest sampling of 1 s) then a CPU with N cores can run at least 2xN fully loaded instances. However most instances are not fully loaded (most furnaces have slow temperature variation and don't require 1 s sampling time) in this case this number can be increase. As such in most practical situations of a modern multicore CPU, the number of running instances are limited by the number of installed serial ports rather than the number of CPU cores.
Q: What are the costs of this system?
The complete costs for an operational HeatMon system can be split in the software license cost and the commisioning costs. The software license cost is dependent by the number of instances needed, and is composed from a base price of 800 € plus an additional price of 300 €/instance. For example a 2 instances license will cost 1400 €, this software cost presented here is just indicative. The commisioning costs are highly dependent on customer needs and location. They are smaller in the case of self-commisioning and we can remotely assist in this process with choice of components and electrical design and modifications. On site assistance may be requested but is limited depending of location, and the associated costs can be quite high.
Q: On how many computers can install the software if I buy a license?
The software can be installed and used on any computers that you own, as long as the number of instances installed on all the computers combined do not exceed the maximum number of instances specified in the license you have. The number of instances discussed here refer to the furnaces control application (htcontrol), the programming and monitoring application (htprog) instances are not limited and can be installed on how many computers is necessary.
Q: What to do if the control application give the "Activation key error" at startup?
If the control application worked before, this error can appear if some hardware changes toke place, or some hardware configurations had been changed. To solve this situation run the setup again but only to the page that ask for key validation, enter the activation key and press the "Validate" button. After that cancel the rest of the setup.
Q: What to do if at application start it give an error that some dll files are missing?
This can also happen when install for the first time and usually happen because the Visual C++ runtime redistributables are not installed or they had been uninstalled by mistake. To solve this run the file "vc_redist.x86.exe" present in the setup package, this will install the runtime redistributables if not already installed. It may also happen if a dll file has been deleted by mistake from one instance BIN forlder, in this case the missing dll can be copied back from the setup package.
Q: What are the serial link parameters that need to be set-up in the furnace temperature controller?
The serial data frame parameters are: data bits = 8 bits, parity bit = even, 1 stop bit. The communication protocol should be set to Modbus RTU. The baud rate should be set to the same value set in the control application at the corresponding furnace settings, the default is 19200 that is good for most cases. If the temperature controller allow the setting of response delay, this can be set between 16 - 20 ms, this will cover the time to switch from transmission to receive in all cases including when the switch is done by the Windows serial driver using the RTS line. The Modbus unit number should be set equal with the corresponding furnace number in the control application, between 1 - 8 corresponding to F1 - F8.
Q: What type of RS485 converter to use to connect with the furnaces?
Since the computers and most common serial extension cards come with RS232 serial ports, a serial convertor need to be used to setup a RS485 communication line. The best solution is to install a serial extension card that come directly with RS485 capability, however such cards are uncommon and expensive. As such the most common solution is the use the existing RS232 serial ports and/or extension cards together with corresponding RS232 to RS485 converters , the RS485 line here is working in half duplex mode the same line being used for both transmitting and receiving. Industrial quality converter are recommended that are able to drive a RS485 line loaded with terminating resistors at both ends, since this give the high noise immunity scpecific to the RS485 communication. Low cost converters that are designed to work only with open line (without terminating resistors) should be avoided since in this case the line become much more susceptible to noise.
To address this problem we offer a dual RS232 to RS485 converter that is able to drive 2 independent RS485 lines loaded with terminating resistors and with idle polarization level to maintain a good noise immunity. See dual RS485 converter .
Q: Can USB to RS485 converters be used instead of native serial ports?
Yes a USB based virtual serial port with intergrated RS485 transceiver can be used but is not recommended. This is because the USB communication and devices are not designed to be used in industrial environment where a higher level of EMI is present that can lead to communication errors, since the USB use both differential and single ended signaling. If used the USB cable should be as short as possible to reduce the interferences.