DanW

I have used both MacTek and Procomsol. Both work. I lke the test utility that MacTek has that reads the primary variable to 'prove' connection to the field device. Several years ago I purchased one made in Eastern Europe. It came with no drivers and the US sales organization blew me off telling me to navigate the Czech or Hungarian site (or whatever) to find the driver. It was returned in short order. As my daddy says, "Son, there's nothing someone can't make cheaper, but you get what you pay for".

One of the last manuals "with schematics". Full 14 page manual attached. Transmation 1045 Instruction Manual 1984 includes schematics.pdf

Does anyone have a schematic for a Transmation 1045 milliamp calibrator in the file cabinet? Mine is deceased and I can't find the service folder I had on it. Dan

It took 8 years, but I finally found a schematic in an original 1984 instruction manual. Register and message me if you're looking for higher resolution copies than those displayed on the page.

You need a pressure switch. The important spec is the one in the column called "over range pressure". The pressure switch needs to have a over range pressure that is equal to or greater than the highest cylinder pressure when the cylinder is newly filled. If the over range pressure is less than the cylinder pressure, the setpoint can be affected/altered/changed by the over pressure. The models below have over range pressures in excess of 70 bar, which is a typical gas cylinder pressure, but you need to establish was pressure your helium cylinders come in at. If you do not have facilities for adjusting the setpoint, then I would recommend that you buy the switch from a vendor who can do the setpoing adjustment for some nominal fee.

If your controller has an X-Y look-up table function (called by different names like characterization, look-up, or linearization), then a relatively small number of points can provide surprisingly close calculated volume values, 0.5% or 0.3% as the tables show. These numbers came from Precision Digital, many of whose process indicating meters have a look-up table. More than once, people have used the converted-to-volume data retransmitted as a 4-20mA output from one of these indicators as a volume input to the PLC because the PLC lacked the math. Dan

Welcome. I hope we can be of help to each other over the years. Dan

Lake County Community College and Elgin Community College both had PLC courses 6-7 years ago. You'd have to check their web sites and see if either still does. Other community colleges are likely to offer an entry level PLC course, too.

See David's reply on another forum here: http://www.control.c...7505#1397001915

Low levels of common mode noise gets rejected by inversion-subtraction on a differential input: RS-485 features a differential input that rejects common mode noise, within the circuit's limits, as shown below: I like the diagram above because it shows the input signals referenced to a signal ground: When a ground loop exists, the measured voltage is the sum of the signal voltage and the potential difference between the signal source ground and the measurement system ground. Note the added Vcm in this diagram: which can appear as the difference in potential between the grounds. Excessive common mode, shown as Vcm, can increase to a level that either - saturates the circuit making it dysfunctional, but not destroying it, or - damages the components due to excessive current/voltage There are a number of web articles on common mode, like the one here: http://www.embedded.com/print/4169569

Precision Digital panel meters have a linearization look-up table with either 10 or 8 break points. You can see their accuracy claim. Pdf is the same as the image below: Horizontal_round_tank_volume_by_10_point_look-up.pdf

You can use a voltage divider, a couple of resistors in series, and measure the voltage across the one resistor whose one side is at the reference or ground (otherwise the analog input sees the full -24V "common mode"). The fraction of the full voltage dropped by the resistor can be lower than the 5V or 10V span of a typical PLC analog input. There are lots of voltage divider tutorials on the web, including some youtube vids that will explain how a divider loads the source (the eddy current device) and how it also affects the accuracy of the measurement by being a parallel resistance with the analog input.

another 2 cents: I had some experience with a submersible ultrasonic transducer in a clarifier. It was a miserable experience. Apparently temperature gradient at different water levels can affect the bounce of the ultrasonic echo, in addition to the density and clarity of the water.

The two most common Modbus formats are 4321 and 2134. I don't think I've ever run into the other two. My comment about the BigEndian only refers to the on-line calculator that I was using, I didn't intend to infer that PeakHMI was using BigEndian format, in fact, it isn't, since the values shown in the screen shots made made no sense, whereas the BigEndian format in the on-line calculator did make sense. I misunderstood the totalizer format. I thought that the technique Reg 40017 = 0002 Reg 40018 = 38,799 Totalizer value (2 x 65536) + 38,799 = 169871 was claimed to be IEEE754, which it isn't. But it seems to be a very reasonable method using a count of the number of auto-resets of the totalizer and the current totalizer value to get a grand total. Floating point does bear the burden of the machine epsilon effect as you described, Add 100 when only 1000 is noticeable.

The Eastech web page says, "Logging with IEEE 754 precision accuracy". IEEE754 floating point is the format for most, if not all, Modbus floating point. The guy who is using decimal values from the different registers and attempting to shoehorn them into a floating point value is blowing smoke. The format of registers 40001-40002, 40011-40012 and 40009-40010 is clearly IEEE-754 Big Endian, byte format 4321: (attempts to change font to place the hex characters at the appropriate byte fail miserably, so you'll just have to work around the lack of formatting) registers 40011-40012 byte 4 byte 3 40011 0011 1110 0001 1010 (decimal 15898) hex 3 E 1 A byte 2 byte 1 40012 1000 1101 0001 0100 (decimal 36116) hex 8 D 1 4 Big Endian 4321 0x3E1A8D14 = 0.1509288 Byte swap 2143 0x8D143E1A = -4.5680773 E-31 Little Endian 2143 0x8D143E1A = -4.5680773E-31 Little Endian swap 1234 0x148D1A3E = 1.4247712E-26 --------------------------------------- registers 40009-10010 0100 0000 0011 1011 (decimal 16443) hex 4 0 3 B 1111 1110 0001 0000 (decimal 65040) hex F E 1 0 Big Endian 4321 = 403BFE10 = 2.9373817 ---------------------------------------- registers 40001-40002 byte 4 byte 3 0100 0001 1101 0010 (decimal 16850) hex 4 1 D 2 byte 2 byte 1 1000 0000 0011 1110 (decimal 32830) hex 8 0 3 E 0x41D2803E = 2.9373817 -------------------------------------------- There's a floating point converter (Big Endian only) at Schmidt floating point converter if you want to try yourself. I don't know what the values represent because the Eastech site does not post a Modbus manual that can be readily found. Most Modbus masters allow a choice of one of two floating point formats. Whatever you have selected to interpret floating point in your HMI master is not using the 4321 Big Endian format, since it interprets the value with a result nowhere near the correct value. I showed all four format possibilities for the 40011-40012 registers, and only the Big Endian 4321 format makes sense. I'm sure it's that way for all the other floating point registers. Poke around PeakHMI until you find the alternative floating point format selection.

The Siemens 'low-end' point level sensor, the CLS-100, could easily distinguish between water and the resin beads (immersed in water) used for water softening. I've never used one or seen one, but the description of the technology for the LC-300 series continuous capacitive sensor could do the same, but I'd strongly recommend trying it (or any capacitance unit) before buying. https://www.automation.siemens.com/mcms/infocenter/dokumentencenter/sc/pi/InfocenterLanguagePacks/Catalog%20sheet%20SITRANS%20LC300/sitransl_lc300_fi01en.pdf

The OP's drawing shows a power supply at 100Vdc. The "thumbnail" warning posted ( I assume it applies to the card involved) states a limit of +/- 20Vdc (common mode). Making the voltage measurements shown on the original drawing is NOT doable, because IN 1 is at 100V above ground, which sees 5x greater common mode than the allowed + 20Vdc. Exceeding the common mode limitation will first peg the readings off scale, then fry the input. The restriction limit of 20V common mode includes the IR drop across the output load up to 20V above ground. If the output load dropped 10V and IN2 dropped 8V, then it would be possible to measure IN2 because the common mode would only be 18V, less than the limit of 20V. Any combination of output and IN2 drops up to 20V means those two voltages can be measured because the combination is within the 20V common mode limit. Any combination greater than 20V means the measurement cannot be made. IN 1 is not measurable with the 20V limitation.

Historically that format is called X-Y plotting. It's used for polarography, or a lissajou pattern, but Whether that particular software implements it, or not, I don't know, but you might try searching for X-Y

error 51 is defined at this HP site: http://h20566.www2.hp.com/portal/site/hpsc/template.PAGE/public/kb/docDisplay/?sp4ts.oid=25484&spf_p.tpst=kbDocDisplay&spf_p.prp_kbDocDisplay=wsrp-navigationalState%3DdocId%253Demr_na-bpl70194-1%257CdocLocale%253D%257CcalledBy%253D&javax.portlet.begCacheTok=com.vignette.cachetoken&javax.portlet.endCacheTok=com.vignette.cachetoken#N10323

You should be aware that Lantronix has a multitude of serial servers. I've used one is called Xpress DR-IAP with a specific optional component for packaging Modbus messages. I used Ethernet on the Modbus master side and serial RS-485 on the Modbus slave side to 3 or 4 slaves. It worked fine. Although the unit was purchased as a Modbus-enabled device, the Modbus component had to be loaded onto a standard Lantronix server unit via an installation file. That's the way they do it. I configured it with Telnet over ethernet. I found their pre-sales support very good. They're capable of assessing what is needed and clarifying which model is needed. I'm not sure that a serial Modbus master can use this particular device, because I can't recall any 'mapping' function to map a slave address to an IP address. How does the server convert an RTU message with slave address like 03 into an IP like 192.168.3.42? Going the other way, an Ethernet Master's message includes the slave device's address which gets unpacked and becomes part of the serial message. But the other way around? Maybe there's a mapping function but since I didn't need it, I missed it. Later posts in this thread seem to indicate some kind of mapping function, so maybe it's there. Please tell us what route you take and how it works out.

Wow. I'm jealous. You get to travel anywhere in the US to go to a trade show. I can't do that, unless it's on my dime, my time. I haven't paid much attention but I'll look closer at the emails coming through.

The OP's graph is NOT typical because it compares the same signal from the different time periods. The most common display shows multiple signals over a common time base. The OP's graph shows the same signal, 6AM to 6PM for 3 different days. I have a similar requirement. Is the recommendation Peak or Citect based on displaying the same signal from different time periods, like the OPs request or do Peak and Citect use a common time base for different signals (a common method for HMIs). Dan

Unless there's some network moderating going on, multiple protocols on a multidrop 485 network can have serious 'collision' issues. That's why the Modbus RTU standard limits a multidrop network to a single master, because Modbus RTU is not sophisticated enough to avoid collisions between packets from different masters - there's no token sharing, like Modbus Plus has. I remember having multiple serial ports in HMI/SCADA PC's so that one serial port could be dedicated to each RS-485 protocol, even splitting Modbus ASCII from Modbus RTU, or from the proprietaries.

This is a very specific question about a Siemens product. You might consider posting it in the Siemens forum.

That's a good diagram of what you're looking for. You should have started with that. I'd suggest you inquire of Red Lion Controls to see if their Data Station Plus can remap the data as required. The Data Station Plus has Master/slave capabilities along with some remapping abilities. I'd email them the last diagram, because that diagram does a good job describing the task at hand. I can't recall how many serial ports a Data Station plus, it might not have 3 serial ports to handle all 3 masters on the RTU side, but you could use a serial-to-ethernet server on one master's output to convert to ethernet, while using serial ports for the remaining two masters.